1. Beyond proud that you're my sister. Have the best day darling!
2. Happy cake day, sissy!
3. Wishing you a day full of love and surprises!
4. A very happy, sassy, classy birthday sis!
5. Saying you're the best sister in the world is just scratching the surface.
6. Let the party begin. Happy birthday, sis!
7. Feeling so lucky to be your sister.
8. Every year you make life sweeter. Here's to another trip around the sun!
9. You’re the icing to my cake. Happy birthday, sister!
10. You rock! Happy birthday, sister.
11. Happy birthday, built-in bestie!
12. Happy birthday to the most wonderful sister in the world!
13. Wishing the best sister in the world a happy birthday.
14. You’re the best sister a girl could ask for. HBD!
15. You mean so much to me. Happy birthday, sister!
16. Happy birthday to my best friend!
17. I’m so proud to call you my sister. Happy birthday!
18. Let's get the party started. Happy birthday, sis! 🥳
19. Happy birthday to my best friend.
20. I feel so lucky to call you my sister. Thanks for being the best!