150 Best Birthday Wishes for Sisters & Sisters-in-Law 2025

In an ideal world, you could harness the energy of a classic 18th-century poet while writing a birthday message for your sister. This is not the average relationship in your life—and your day one confidante definitely deserves the prose you’d find in iconic literature. Growing up with a sister is special to say the least. She’s someone who’s seen you through your unfortunate middle school phases and early-adulthood milestones. She’s the outlet for your frustrations about your parents. your ex, and that one old friend she never liked anyway. Plus, you’ve probably ~~stolen~~ shared your fair share of each other's clothes, makeup, accessories, and maybe even personalities. So no, you don’t want to celebrate her with a basic Instagram caption or mid-rate birthday card message. Yet when the time comes to put pen to paper (or thumb to smartphone screen) and voice your admiration for this queen, it's easy for words to escape us.

That’s likely why you’re here, where you’ll find several lovely dedications worthy of your favorite person's special day. We’ve assembled a list of captions, messages, and well-wishes galore. From funny birthday captions to sweet ones that might leave her in tears (happy ones). And if you’re vying for the Best Sibling Ever title, you should also grab her a thoughtful gift that she'll cherish (and that you can hold against her when your birthday comes around.)

Funny Birthday Wishes for Sister

Sisters are amazing, especially yours. Happy birthday!
Birthday candles aren’t the only thing getting lit this weekend. Happy birthday!
Happy birthday! This year, your present is my presence.
Happy birthday, love you and all. But not a huge fan of your choice cake flavor.
Since it’s your birthday, I’ll share my fries with you. Maybe.
I love you, and I almost forgive you for every time that you've snitched on me.
Let’s drink champagne and dance on the tables (until we’re politely asked to leave).
I know you’re a [insert zodiac sign here], but try not to cry while we’re singing happy birthday, okay?
Happy birthday to the responsible sister who said Mom’s gifts were from “both of us” when you did all the work.
To quote the great poet 50 Cent, we're literally gonna party like it’s your birthday.
May you capture the perfect Instagram picture today, queen.
Happy birthday to a dime who’s in her prime!
Remember to smile awkwardly as everyone sings “Happy Birthday” tonight!
I’m so glad I have someone who I can complain about our parents with. Happy birthday!
Happy birthday! Signed, the only normal person in our family.
I love you more than I love binge-watching Netflix. And I love that a lot.
Happy birthday! May the hangover be mild tomorrow!
I’m smiling because we’re sisters, and I’m laughing because there’s nothing you can do about it.
Happy birthday! Your transformation into Mom is nearly complete.
Happy birthday, sis. Sorry for always stealing your clothes, but in my defense, you have good taste!
No one understands me like you, because no one else grew up with our bizarre family.
Happy birthday! Now that we’re officially old, there’s no way I’m staying at your party past 9:00 pm.
Happy birthday! It’s officially time to start using a retinol.
My birthday wish for you is that you bag a hottie at the bar tonight.
Fun fact: birthdays are good for you! Statistics show that the more you have, the longer you live.
I’m usually the star of the family, but I’ll let you have the spotlight for today.
I can’t wait to celebrate you tonight! But also, could I borrow that black leather jacket I like?
I love you, even though you ripped my favorite sweater in middle school. Happy Birthday!
There’s no one I’d rather drive around our hometown with while drinking iced matcha lattes. You're the best!
Wishing you years of happiness and mild hangovers (P.S.—I already got you Advil for tomorrow.) Happy Birthday!
There’s no one I’d rather talk sh*t with when things don’t go our way with mom and dad. Thanks for always being there. Happy birthday!
Can’t wait to spend way too much at dinner tonight. You deserve to be splurged on!
I told Mom what gift you wanted, so it's basically from both of us. You’re welcome!
I’m so lucky to have someone to escape to the bathroom with during awkward family functions. Happy birthday!
I hope you enjoy your cake—I picked it out, so you’re welcome.
I’m only wishing you a happy birthday because you have a bottomless well of blackmail on me.
Happy birthday, legend. You couldn’t get rid of me even if you tried. (And try you have.)
Happy birthday! I can always trust that you’ll (loudly) tell me when I look stupid.
Happy birthday! I’ll try not to cry too hard during my speech for you tonight.
I can’t wait to see what ridiculous “because it’s my birthday” justification you come up with this year!

Birthday Wishes for Younger Sister

Happy birthday to the sister who keeps me up to date on TikTok trends.
I’ll always have your back. Happy Birthday to my mini me!
Happy birthday to my favorite person in the whole wide world.
No one gets me like you do. Happy birthday, sis.
On this day, someone special joined the world, and I’m so lucky that she also joined my family.
I’m so happy we got to grow up together. Happy birthday to my first best friend!
I hope your birthday is as magical and sweet as you are.
I hope your [partner/boyfriend/girlfriend/etc.] is pampering you for your birthday since I can't be there. You deserve it!
First you're sour, then you're sweet. Well, sometimes. Happy birthday to my personal little Sour Patch Kid!
We might not be together today, but I’ll be celebrating your birthday anyway!
You’ve grown so much in the past year, and I’m so proud of you. Happy birthday, sis.
I hope you know that you are very, very loved, today and every day.
You’re building such a meaningful life for yourself. Take time to enjoy it, especially today.
You have been so strong in the face of a tough year. Here’s to starting a brand new and brighter one.
Sending you a birthday wish wrapped with all my love.
You don’t get to choose your family, but I would have chosen you. Happy birthday!
You live your life in a way that makes every day worth celebrating. Happy birthday, sis!
Your birthday is the first day in a new 365-day journey. I know you’ll make it a good one.
Happy Birthday to the life of our family (and the party!)
No one gets you like a sister, and I’m so glad you’re mine. Happy birthday!
This year, I wish for you to know how special and incredible you are.
Happy birthday to the sunshine of our family! You make everyday extra bright!
Life was pretty dull until you came around [insert age] years ago. How lucky are we that you were born into this family?! Happy birthday, little sis.
I hope today is filled with your two favorite thing: lots of love and cake. Happy Birthday!
Happy birthday! You’re welcome for making you cool.
I might have been mad when Mom and Dad brought you home, but you’re actually alright.
Happy birthday to the sis who never told our parents about me sneaking out to parties. Love ya!
It’s time to finally start acting your age! (Just kidding).
Happy birthday to the little sis who was always willing to join in on my shenanigans!
Happy birthday! Sorry I took all the good genes before you got here.
Who would have thought my annoying little sister would grow up to be so cool?
Even though you roast me for being a millennial daily, I still hope you have a happy birthday.
Happy birthday! I forgive you for being younger than me.
Enjoy your youth now. The hangovers only get worse.
Happy birthday! My gift is the fact that I literally taught you everything you know.
Counting all those times I drove you and your friends around in high school as my eternal present to you.
I can't believe you're [insert age]! I still remember you being [one year younger] like it was yesterday.
Not going to lie, I was hoping mom and dad brought me a brother back from the hospital. But you turned out to be alright after all!
If I could have picked my sister, it'd still be you, hands down. Happy birthday, little sis!
To be honest, I still see a little girl with pigtails when I see you. How did [insert age] years fly by already?! Thanks for being my IRL babydoll (and for letting me put lipstick all over your infant face).
You’re essentially my human sequel. And I love that for you.
I’m still in disbelief that you’re not 12 years old anymore. I love you more than words can express!
Thank you for always keeping me honest and on trend. Everyone deserves someone like you in their life.
I know that I basically raised you, but I learn so much from you every day. Happy birthday, my angel.
There’s no way time is flying this quickly. Please stay my baby sister forever.

Birthday Wishes for Older Sister

Happy birthday to the girl who knows me better than I know myself!

My gift to you was telling you to stop wearing that side part last month. You're welcome!
Happy birthday to someone who taught me everything I know about applying eyeliner.
You’re aging like a fine wine.
Happy birthday! You may be older, but I’ll always be wiser.
Happy birthday to my life's guiding light.
Wishing you a birthday that’s fit for a queen.
I think you’re supposed to get finer and wiser with age? That’s okay, there’s always next year.
Happy birthday to my favorite elder!
Happy birthday to the older sister all my friends had crushes on.
Because it’s your birthday, I’ll admit that you are actually cool. But only today. And maybe next year, who knows.
You’re not getting older, you’re leveling up!
I’m so happy we’re growing old together, and that you have a head start.
Happy birthday! I couldn’t have asked for a better big sister.
I know you’re only 30, but according to TikTok, that makes you an old lady now.
Happy birthday, sis! Thanks for always picking me up and letting me stay on your couch when I had a fight with our parents.
Happy birthday to the sister who is forever young at heart.
Happy birthday to the favorite daughter—we all know it!
I’m lucky enough to always be mistaken for you, so I guess I'm the one who really got a gift! Happy birthday, sis! I hope today is as beautiful as you.
Happy Birthday to the girl who teaches me to be a better daughter, sister, friend, and person!
Sending you more years of special moments and memories together <3
Does teaching you a new TikTok dance count as a good present?
To many more adventures around the world! Happy birthday to my travel buddy and sister!
My greatest gift to you was actually the day *I* was born.
Happy birthday to my globe-trotting sister! Wishing you many more adventures this year.
I’m forever indebted to you for giving me a personality.
I’ll try my best not to embarrass you today, but sometimes my best isn’t hard enough.
Happy birthday to my blood-related bodyguard. I’m lucky to have you by my side.
Thank you for making life a little bit lighter on the darkest of days.
There are simply not enough greeting cards in the world to capture my love and appreciation for you.

Sweet Birthday Wishes for Sister

I wish for all your birthday wishes this year to come true.
My birthday wish for you is that you get all the great things you deserve this year.
Happy birthday to someone who makes the world a brighter, kinder place.
I hope you see yourself the way I see you: fabulous, kind, strong, smart, funny, and wonderful.
You’re one of a kind, and I love you so much. Happy birthday!
Happy birthday to someone who has a big heart.
Happy Birthday to my bright and selfless sister! To many more bright and meaningful moments together.
I’ll always have your back, and am grateful you’ve always had mine. Happy birthday, sis!
Sending you more years of special moments and memories together. I love you so much, sister!
I hope you never forget how truly special you are. Happy birthday to my absolute ride or die.
Every day, I thank the powers that be for placing you in my life. You deserve every good thing today.
I simply can’t remember what life was like before you, and I don’t want to. Happy birthday!!!
There’s a reason we’re sisters in the lifetime, and not schoolmates or neighbors. It’s you and me until the end, baby.
Happy birthday. You’re my hero from now until forever.