What to write · Birthdays

What to write in a birthday card for your sister

Pick a birthday message for sister that teases and tugs at the heart in one breath, and a real printed birthday card heads to her mailbox from your phone.

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Messages you can use

Copy one as it is, or change a few words so it sounds like you.

No one knows me like you do, and that includes the embarrassing parts. Thank you for keeping most of them quiet. Happy birthday, sis.
You were my first friend and you are still my favorite. I hope this year brings you all the good stuff.
Happy birthday to the only person who remembers all of my worst haircuts.
We are officially at the age where we complain about sleep and talk about our knees. At least we are doing it together. Happy birthday!
I still have the photo of you from our road trip. Do not worry, I will only use it if you stop answering my texts. Happy birthday!
Growing up with you made my childhood so much better. I would not trade a single argument over the bathroom. Love you.
Sis, you are the one I call first. Have a great day.
You have been there for me through every rough patch, and I hope you know I am here for you too. Happy birthday.
I think of you whenever I hear a song we used to sing together. Hope your day is full of music and laughter.
Happy birthday, sis. You are still the only one who can finish my sentences and my fries.
I would give you the shirt off my back, but you already borrowed it in high school. Happy birthday!
Distance cannot change how close we are. I wish I could be there with you today. Sending all my love.
I am proud of the woman you have become, and I am glad I get to say I knew you when you were bossy.
Sis, I am booking us a weekend. No schedule, no excuses and I pick the snacks. Happy birthday.
You are the only person who can make me laugh at the worst possible time. Thank you for that. Happy birthday.
I love you, sis. Happy birthday. Call me later.
We both know who the favorite is, and I am sending this card anyway. Happy birthday, sis.
I hope someone treats you today the way you treat everyone else. You deserve a celebration. Happy birthday to my sister.

Ways to sign off

Love, · Your sister, · Love you lots, · Your favorite sibling, · XO,

How to write it

A birthday message for sister can poke fun and say ’I love you’ in the same breath, as these examples do. A sister is often the one person who remembers everything, including the embarrassing parts. That is what makes cards to sisters so fun to write. You can lean on shared jokes, childhood stories, and the things only she would understand, and skip the formal stuff.

Pick a memory, a habit of hers you love, or a way she has been there for you. Add one sincere sentence and one playful one. Whether you live down the street or across the country, a card in her mailbox is a nice surprise. Choose a message below and change a detail so it sounds like you wrote it on your own. We print it on a postcard in a handwriting-style font and mail it, wherever she lives.

Bring up a childhood memory, like a road trip or a shared room. Only a sister will understand the reference.
Include one sincere line about what she means to you. Siblings often skip this, which makes it hit harder.
Use a nickname or an inside joke. It shows the card is from you and no one else.
If you live far apart, say you miss her. A mailed card beats a text when you want to show effort.
Poke fun gently. Teasing about her taste in music is fine, teasing about her looks or age is not.

Designs that fit

Pick a design, paste your message, and we print it in a handwriting-style font and mail it. Cards from $2 with postage; letters from $3.

Questions people ask

What if my sister and I tease each other a lot?

Then a joke belongs in the card. Add one sincere line too, since siblings rarely say what they mean out loud. The mix of funny and real is what makes a card stick.

Can I send a printed card if I live in another state?

Yes. We mail to any U.S. address with postage included. A 4x6 postcard starts at $2, and you see a preview of the front and back before you pay.

More guides

Everything on what to write

Found the words? We will mail them.

Choose a card or a letter, add the address, and see a preview before you pay.

Send it as a card