43 Best Ways to Say ‘Happy Birthday’ to a Sister or Sister-in-Law

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No matter if the relationship with your sister is close or complicated. Full of fun or full of strife, it’s important to celebrate your sibling’s birthday. And, the least you could do is to send a text or post a message on social media. 

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Here are some ideas on how to say “happy birthday” to your sister or sister-in-law. Some of the messages are intended to be funny or even a little sarcastic. Other words will help you express how important your sister is to you. Some you may be able to use to pay tribute to a sister who died

Hopefully, these messages will give you inspiration on how to format the perfect message for your own sister. But remember, when it comes to talking with family members, it is best to speak from the heart. 

Funny ‘Happy Birthday’ Messages for a Sister

Example of a funny "happy birthday" message for a sister over an image of cupcakes

Most of the time, if you can be funny or sarcastic with your sister, that means you have a close relationship. Here are some somewhat-funny messages for your sister as she celebrates her special day. 

1. I smile because you are my sister. I laugh because there is nothing I can do about it. Happy birthday, sis!

“You can pick your friends, but you can’t pick your family.” Maybe a therapist said this to you once. Since you are stuck with them, you may as well figure out how to get along with them.

2. Happy birthday to mom’s second favorite daughter!

Of course, personalize this message, so it works for your situation. It is sure to get an eye roll from your sister when she reads it.

3. Sisters are a lot like sprinkles on top of an ice cream sundae. You can get by without them, but what would be the fun in that?

Who doesn’t love sprinkles? Exactly! Treat your sister as if she is your favorite ice cream topping.

4. Having a sister as awesome as me is the only present you need.

Your sister was probably going to return your gift anyway, so why bother? 

5. Happy birthday, sister! You look exactly the same . . . except older.

Do you have a sister who is worried about aging? Send her this message to tease her about it, and also buy her a bottle of Oil of Olay to accompany the birthday wish.

‘Happy Birthday’ Messages for a Big Sister

Older sisters are special, especially if they take the time to help you through life. Maybe your older sister was the one who taught you to put on makeup or drive a car. Perhaps she gave you advice on how to handle your parents or get through high school. 

It’s time to say birthday to your older sister. Here are some phrases to help you. 

6. Happy birthday, sister! When I was little, I looked up to you as my role model. Now that I’m older... nothing has changed.

Have you always looked up to your older sister? Let her know how much she means to you. Perhaps you are learning how to be a great mom or a wonderful grandmother from your older sister. 

7. Remember, no matter where you go or what you do, you will always be older than me. Happy birthday to my older sister!

Gently tease your sister about her age, if you think she can handle it. You may also consider finding poems about aging to share with a sister on a landmark birthday. 

8. Even though we are very different, we will still always be sisters. I love you dearly! Happy birthday!

Do you and your sister disagree about politics, religion, or child-rearing? Having a different worldview from your sister can put a strain on your relationship. Put those differences aside on her birthday, and let her know how important she is to you.

9. Happy birthday, sister! You are so smart, pretty, and vivacious (for your age.)

Are you the queen of back-handed compliments? Share this one with your sister on her birthday. She can’t get too mad at you for calling her old since you also called her “smart, pretty, and vivacious.”

10. Happy birthday sister, from the exact same mister!

You have heard of sisters from another mister. Here’s a way to celebrate the birthday of someone from your exact same genetic pool. 

‘Happy Birthday’ Messages for a Little Sister

Example of a "happy birthday" message for a little sister over an image of colorful lights

It’s your little sister’s birthday! Even though you may think that she gets all the attention in the family, take time to send her a sweet birthday message. Here are some phrases to inspire you.

11. Happy birthday, little sister! You aren’t nearly as annoying as you used to be!

Let’s face it. No matter how close you are with your sister, she has annoyed you at times. Maybe she stole your clothes or told on you when you tried to sneak out of the house. Regardless of her past mistakes, it is time to let bygones be bygones and have a healthy, supportive relationship with your sis. 

12. Dear sister, I know there have been times when I have teased you, pestered you, and told on you. But I want to tell you that I think you are an amazing person. Happy birthday to the best little sister a girl could have. I love you!

Have you not been kind to your sister in the past? Take the high road and admit your mistakes. Make up for the past mistreatment by being kind to your sister now.

13. Happy birthday, sister! I know mom and dad were worried, but I guess you turned out all right in the end.

Are you looking for another back-handed compliment to wish your sister a happy birthday? Here’s one for the win. This is the perfect message for a sister who caused your parents strife during or teen years. 

14. Happy birthday, sister! I loved you yesterday, and I love you still. I always have, and I always will.

It’s important to tell others how we feel about them. In fact, maybe that should be a part of your birthday resolutions this year -- to say to others that you love them. Can you think of a better resolution than that?

15. With each passing year, you shine a little brighter! Happy birthday to my little sister!

Has your little sister grown up to be someone you look up to? Let her know! Chances are, she feels the same about you.

Short ‘Happy Birthday, Sister’ Messages for a Cake or Banner

Are you in charge of the cake or the banner for your sister’s birthday party? That’s quite the responsibility. Here are some messages that won’t get you in too much trouble from your mom.

16. One year closer to death!

We know this message may make people cringe, but it’s a tiny bit funny. Consider who will be around to read this cake or banner before committing to these words.

17. You are sweeter than this cake! Happy birthday!

Are you struggling to come up with a nice message for the cake besides, “happy birthday!”? This is a lovely, appropriate message to put on a cake.

18. Age is just a number. False: Age is a word.

Is your sister a fan of The Office? She probably has seen this meme that features the face of Dwight Schrute. If she’s not a fan of the show, this joke probably won’t work well.

19. We love you, (name)!

Purchase a customizable banner for your sister’s birthday. Not only could you use it for your sister’s birthday, but for other celebrations as well.

20. Blow out the candles before the fire alarm goes off!

Are there an awful lot of candles on your sister’s birthday cake? Why not tease her about it? 

21. Happy birthday, sister!

Why complicate matters? Simply wish your sister a happy birthday, and tell her that you love her.

Famous ‘Happy Birthday, Sister’ Quotes to Share

We give you permission to share these quotes by famous and sort-of famous people with your sister. Sometimes it’s just easier to turn to a quote book instead of coming up with a clever saying on your own.

22. “Sisterhood is Powerful” by Robin Morgan

You might appreciate this quote on a couple of different levels. Not only does it celebrate the common bond you might share with your sibling; this quote is also the title of a book from the 1970s that was edited by Robin Morgan. The book was a collection of essays written by feminist authors – celebrating Sisterhood among all women.

23. “For there is no friend like a sister
In calm or stormy weather;
To cheer one on the tedious way,
To fetch one if one goes astray,
To lift one if one totters down,
To strengthen while one stands.” by Christina Rossetti

Christina Rossetti is a prolific English poet who wrote in the middle and late 1800s. 

24. “Sisters are different flowers from the same garden.” by Unknown

However, if you get to choose your flower, don’t decide to be a marigold. Marigolds smell bad.

25. “A sister can be seen as someone who is both ourselves and very much not ourselves – a special kind of double.” by Toni Morrison

We love this quote by acclaimed author Toni Morrison. Morrison’s most famous works were “The Bluest Eye,” “Song of Solomon,” and “Beloved.”

‘Happy Belated Birthday, Sister’ Messages

Example of a "happy belated birthday" message for a sister over an image of balloons

You’re only human. At some point in your life, you will probably have to beg your sister’s forgiveness for forgetting her birthday. So here are some messages to send that may get you out of the doghouse.

26. “I owe you two glasses of champagne instead of one! Happy belated birthday, sister!"

If you have to apologize to your sister, it’s better to do it with champagne. 

27. “I have no valid excuse for missing your birthday last week. Please accept my apology.”

You probably know your sister better than anyone. Some may forgive you of your oversight easily. Others require a formal apology.

28. “Your friends are so rude! I can’t believe they wrote all those things on your Facebook page yesterday about how you are getting older! I bet you wish they were all like me, who chose to ignore your birthday completely!”

You could try this tactic, but it may not work. 

29. “I am so lucky to have the best, most beautiful, forgiving sister in the world!” Happy belated birthday, sissy!”

Compliments tend to cushion apologies. 

30. “I could come up with a list of excuses on why I didn’t wish you a happy birthday yesterday. But, you know me too well. Sorry, I just forgot.”

If your sister knows you well, you aren’t going to be able to sugarcoat your late birthday wishes.

31. “I know my birthday wishes are late – but they are sincere! Happy birthday to the best sister in the world!”

Of course, getting your sister a fantastic gift might help the situation.

‘Happy Birthday, Sister’ Messages for Your Twin

Do twins even have to wish each other a happy birthday? Maybe they can communicate their message using twin ESP. 

Here’s a message to share with your twin sister if you aren’t on the same wavelength.

32. “Happy birthday to us! Happy birthday to us! I’m lucky to have you! Happy birthday to us!”

You sang these words in your mind, didn’t you?

33. “Happy birthday to my older sister! You may only be older by four minutes, but you are still older than me!” 

When you’re a twin, those minutes count!

34. “You can always depend on me to NOT forget your birthday! Happy birthday, dear sister!”

If you do forget to wish your twin a happy birthday, please see the previous section of this article.

35. “Even if we weren’t identical twins, you would still be my best friend in the world. Happy birthday, sister!”

Share this message if you are lucky enough to have a strong bond with your sis.

36. “Happy birthday to the other pea in my pod!” 

Is this a cheesy greeting? Yeah, probably. But it still gets the point across.

37. “Hey sis! Have you ever wondered if Mom or Dad could have accidentally mixed us up when we were infants? Maybe I’m you, and you are me! Oh well, happy birthday!”

Share this message if you want to keep your twin from getting any sleep that night.

38. “There’s no one else in the world I would rather share this special day with than you! Happy birthday to my twin sister!”

Share warm fuzzies with your sweet twin sister!

Inspirational ‘Happy Birthday, Sister’ Messages

Example of an inspirational "happy birthday" message for a sister over an image of confetti

Life is too short! You need to tell others what they mean to you whenever you have the opportunity. Here are some inspirational birthday messages to share with your sister. Please note that some of these messages might make your sister cry, so send them at an appropriate time of day. 

39. “I can’t imagine going through life without you, sister! You were my role model when I was young, and you continue to be the person that I most admire! Happiest of birthdays to you, special lady!”

Who do you most admire in the world? Let that person know how much you look up to them!

40. “You are my sunshine, sister! Every time I see you, you brighten my day. I love you! Happy birthday!”

You could always accompany this message with a link to either “You Are the Sunshine of My Life” by Stevie Wonder or “You Are My Sunshine.”

41. “Life wouldn’t be nearly as fun without you in it! Happy birthday, sister!”

Do you enjoy being around your sis? Let her know!

42. “Sister, there are so many things I admire about you – including your patience, your beauty, and your zest for life! Happy birthday to my amazing sister! I love you so much!”

Of course, list the qualities that would apply to your sister. 

43. “I hope your family treats you like a queen today! You truly deserve it! Happy birthday to you, dear sister!”

Perhaps you could accompany this message with the gift of a tiara and wand. 

‘Happy Birthday, Sister’ Messages for a Sister Who’s Your Best Friend

The combination of best friend and sister is a force that can’t be broken. If you’re lucky enough to enjoy this close-knit relationship, celebrate it! 

44. Happy birthday to my ride or die, my BAE, my sister, my love! I can’t imagine life without you!

By the time you read this, the slang for “best friend” may have changed. Definitely insert and adjust the common vernacular in place of our poor attempts at being cool.

45. Sorry for the midnight text, but I wanted to be first to wish you a happy birthday!

A good sister goes to extra lengths to wish a happy birthday to a sister.

46. I know we’re spending the day together and we already spoke on the phone, but I wanted to let you know I love you so much! I hope you have a glorious birthday!

If your sister is your best friend, you may communicate dozens of times a day. Use one opportunity to tell her what she means to you.

47. I know that we don’t agree on everything, but you’re still my best friend AND sister. I’ll be there for you forever — even if you are dumb sometimes.

Reassure your sister that there’s nothing she could do to spoil your friendship.

48. Happy birthday to the person who knows me better than anyone else in the world.

Your best friend, who is also your sister, not only knows your current secrets, but she also knows the secrets of your youth.

49. Happy birthday, sister! I believe this year will bring wonderful things to your life!

Perhaps your sister has been struggling. This message will reassure her that good things may be on the horizon.

50. Happy 50th! I can’t wait to see what adventures are waiting for us as we enter the next decade of life! 

Is your sister celebrating a milestone birthday? Celebrate!

‘Happy Birthday, Sister-in-Law’ Message

Your sister-in-law may have been a part of your family for a few months, a few years, or decades. Here are some birthday messages to share with someone who chose to be a part of your family.

51. I am so excited to finally say this — ‘happy birthday to my sister (in-law)’! I have wanted a sister all of my life! You were worth the wait!

Sometimes sisters-in-law fill a role that took a long time to fill! 

52. Happy birthday to a wonderful person who has questionable judgment in men. (Sorry, brother! But you know you married up.)

Can your brother and sister-in-law handle teasing? Here is a somewhat funny message to share with your sister-in-law on her birthday.

53. Happy birthday, sis! Can’t wait to celebrate with you!

Sometimes adding the “in-law” to your sister-in-law’s title doesn’t feel necessary.

54. Happy birthday to my sister-in-law who chose to be part of our family. We are so happy you did!

Celebrate those sisters-in-law who choose to take an active role in the family. 

55. Happy birthday! Even though you aren’t officially my sister-in-law any more, I am lucky to call you friend.

Perhaps your sister-in-law is no longer officially part of the family. Here’s a message to send to her on her birthday if you are still on good terms.

56. I don’t tell you this enough, but I am so thankful you are a part of our family! We love you! Happy birthday!

Use the occasion of your sister-in-law’s birthday to share how you feel about her.

57. Hooray! It’s your birthday! I hope my brother treats you like a queen today!

Trying to find a way to say “happy birthday” without using that tired, old phrase? Here’s an example of how to do it. 

‘Happy Birthday, Stepsister’ Messages

Hollywood seems to love portraying stepmothers and stepsisters as evil. But, chances are, your step-sister isn’t trying to squeeze her giant foot into your glass slipper. (Whose dumb idea was it to create shoewear made of glass, anyway?) 

Here are some ways to say happy birthday to a sister from another mister (or misses). 

58. Happy birthday to the best step-sister in the world! I am so happy you are a part of my life!

Reassure your step-sister that she is a welcomed member of your family.

59. Happy birthday! I wish I could be there to celebrate with you, but we will have to have our own party when I visit next month.

Are you sending a birthday message from afar? Here’s an example of how to do this.

60. Even though our relationship had a rocky start, I am thankful that you are my step-sister. I’m looking forward to celebrating with you for years to come.

Some step relationships don’t start off well. Hopefully, yours has mended enough to wish your step-sister a happy birthday.

61. Happy birthday to my surprise little sister! Even though you stole my role as the baby in the family, I am thankful for you every day.

Of course, your family dynamics probably changed with the addition of a sibling. But, hopefully, your relationship is stable enough to joke about it.

62. Happy birthday, sister! I love you!

Perhaps you don’t feel the need to designate your sister as a “step.”

63. Happy birthday to the world’s coolest step-sister. My coolness factor increases tenfold when I’m with you!

Here’s one example of how to compliment someone who you don’t know well — but would like to know better.

64. We are sisters by chance but friends by choice! I hope you have a great birthday!

This message would work for biological sisters or stepsisters.

Religious or Spiritual ‘Happy Birthday, Sister’ Messages

Some people avoid bringing up their spiritual beliefs when offering birthday messages to friends or extended family. However, if you’re lucky enough to share the same spiritual beliefs as your sister, you might consider referring to your shared faith when wishing her a happy birthday. 

Here are some spiritual or religious “happy birthday, sister” messages.

65. Have a blessed day, sister!

Here’s a short but sweet spiritual birthday message.

66. I hope you know that my prayers are always with you – no matter how far apart we are! Happy birthday!

Let your sister know you’re praying for her every day.

67. You have brought much joy to people’s lives. May God bless you with the same happiness you bring for us every day!

Is your sister known for spreading joy? Celebrate her kind and caring personality!

68. May the love, grace, and peace of God be with you on your birthday and for the rest of your life!

What more could anyone need for their birthday?

69. Every day is a great day to celebrate God’s wonderful works. Today, I celebrate you! Happy birthday!

What other wonderful works of God will you celebrate today?

70. Today, I am thanking God for making you my sister! You are a blessing to our family! Happy birthday!

A thankful heart is a happy heart. So give thanks to the Lord, for He is good!

71. I am so thankful that you are my Earthly sister and my sister in Christ! Happy birthday!

If you share this type of special relationship, celebrate it!

72. Today, and every day, may God’s grace give you every possible reason to smile! Happy birthday!

Remind your sister to celebrate her birthday while celebrating God’s gifts at the same time!

‘Happy Birthday, Sister’ Posts to Share on Social Media

Actually, all of these posts would be appropriate to text, email, write on a birthday card, or share on social media. However, here is a stand-alone category for social media birthday posts.

73. My sister isn’t on Facebook. But since I’m friends with many of the people she interacts with daily, I wanted to remind you all that today is her birthday! (And it’s a BIG one!) If you see her, wish her a happy day!

Here’s an example of how to wish a happy birthday to a sister who isn’t on social media.

74. Happy birthday to my amazing sister and best friend!

Social media users know that you can post a message directly to their account, or you can post a message on your page and tag your sister.

75. Thirty-eight years ago today, my mom went to the hospital. As she was leaving, she told me that she would bring back a present for me. I couldn’t wait to see what it was! Imagine my disappointment when she brought home a dumb baby. It took me a few years, but now I understand that I received one of the best gifts of my life that day. I love you, sister! Happy birthday!

Tell the story of your sister’s birth to celebrate her special day.

76. Happy birthday to you! Happy birthday to you! Happy birthday, dear sister! Happy birthday to you!

Maybe you have your own special birthday song that you can “sing” over the internet.

77. Happy birthday to one of the biggest blessings in my life! I love you sister!

Life’s too short to hold back on your feelings! Tell your family and friends that you love them and that they are important to you!

Other Ways to Make Your Sister Feel Special

While sending a text or a message on social media might make your sister smile, why not go the extra mile to wish her a happy birthday! Arrange for lunch to be delivered at work. Send her flowers. Or simply give her a call!

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