Mothers-in-law are often the subject of jokes and stereotypes. But sisters-in-law? They’re harder to pin down.
Some sibling-in-law relationships are warm. Others are downright frosty. Many are complicated by mixed feelings or a simple lack of contact.
However you feel about your sister-in-law, it’s important – nay, mandatory – to wish her the best on her birthday. Of course, the exact form your birthday greeting takes is up to you. We’ve put together the following list of birthday wishes for a sister-in-law to help you find the perfect sentiment for your unique, special, and possibly complicated-as-all-get-out relationship.
Sweet & Sincere
Here are some just plain nice ways to wish your sis-in-law a Happy Birthday. If you have particularly warm feelings for the birthday girl, you might also want to see these “Happy Birthday, Beautiful” messages.
- Happy Birthday to my amazing sister-in-law! You may not have been born my sister, but you’re my sister all the same.
- Thanks for being the best sister-in-law ever. Hope your birthday is as awesome as you are!
- Happy Birthday to the sweetest, smartest, and just plain awesomest sister-in-law in the world!
- One of the fringe benefits of being married to your brother is that I get to have you for a sister-in-law. Hope you have an amazing birthday – you deserve it!
- Happy Birthday to someone who isn’t just my sister-in-law, but also my soul sister. Hope you have a fantastic day!
- Best birthday wishes to the best sister-in-law ever! Thank you for being you!
- Happy Birthday to my sister-in-law, who has always been like a real sister to me. You are the best!
- Happy Birthday to a lady I’m proud to call my sister-in-law.
- Happy Birthday to one of my favorite people in the world, my sister-in-law!
- Happy Birthday to my wonderful sister-in-law. Even if you weren’t family, I’d still love you and want you in my life.
Cute & Funny
Here are some birthday wishes for a sister-in-law who appreciates a little humor. You can find tons more ideas in this collection of funny birthday messages.
- Just wanted to let you know that I’m thinking about you on your birthday, sister-in-law. Mostly I’m thinking about how weird it is that a nice girl like you married someone like my brother!
- Happy Birthday to my amazing sister-in-law, who generally has good judgement but chose to be part of our nutty family for some reason.
- Happy Birthday to the world’s second best sister-in-law!
- Just wanted to wish you a Happy Birthday. Oh, and tell my brother he still stinks!
- Having you for a sister-in-law kinda makes up for the fact that my brother is such a jerk. Happy Birthday!
- Happy Birthday to my remarkable sister-in-law. You have to be remarkable to put up with my brother every day!
- Happy Birthday to my sister-in-law, who is way too cool to be related to me by blood.
- May you spend your birthday relaxing, having fun, and being completely slaved over by my brother!
- Happy Birthday to my brother’s better half. His way, waayyy better half!
- Happy Birthday to my sister from another mister!
Finally, here are some inspiring faith-based birthday greetings for a sister-in-law.
- Happy Birthday to my wonderful sister-in-law! May God bless you with joy and love, on your birthday and every day.
- I am truly blessed to have a sweet and caring sister-in-law like you. Hope you have a wonderful birthday!
- As a child, I always wanted a sister like you. It took awhile for my prayers to be answered, but I’m so grateful they were. Happy Birthday!
- I thank God for giving you life, and for bringing you into my life. May you have a wonderful birthday.
- Having a sister-in-law like you is one of my greatest blessings. Happy Birthday!