What To Write: Happy 18th Birthday Wishes

An 18th birthday is a big milestone on the way to full-fledged adulting. An 18th birthday opens so many doors. You can go skydiving. Buy a lottery ticket. Get a tattoo. Official adulthood certainly has its benefits.

So what exactly do you say in a birthday message for an 18-year-old? Whether you want a message that’s short or long, sweet or sappy, cute or heartfelt, we’ve got some awesome ideas for what to write in an 18th birthday card.

For Her 18th Birthday

She’s all grown up now and you need the perfect happy 18th birthday message for the young woman in your life.

Dream big dreams this year!
You really know how to shine.
May your 18th birthday be as flawless as you!
Someone as lovely as you deserves an amazing day!
Celebrating your birthday and the wonderful woman you are.

For His 18th Birthday

When a special guy is becoming a man, you need an 18th birthday message that captures exactly what he means to you.

A great guy like you deserves an incredible 18th birthday.
You’ve grown into a good man.
Be adventurous and try new things. This is going to be an amazing year for you!
Your 18th birthday is a chance to celebrate the man you’ve become and look forward to everything that’s still ahead.
Hope your 18th birthday is totally classic.

For A Friend's 18th Birthday

Where would we be without our closest friends? Definitely having a lot less fun. When you need a happy 18th birthday message for a friend, think of all the good times you’ve shared leading up to this special day.

So lucky to have you as my best friend.
Hope your birthday is crazy fun — just like our friendship.
I love how we’re always there for each other.
Can you believe we’re actually adults?
I hope we’re friends until you’re 118! We’re gonna look pretty cute as little old ladies.

For A Family Member's 18th Birthday

Maybe you just need a short and sweet 18th birthday message for your nephew or niece. Your grandson or granddaughter. Or any other family member who’s about to embark on the journey towards adulthood.

I love watching you grow up!
Your 18th birthday is the start of so many exciting adventures.
Hope this year will inspire you.
This is the beginning of the greatest time in your life.
You’re 18 — there’s no turning back now!

Browse our assortment of 18th birthday cards, then use one of our ideas above or write your own happy birthday message before sending. Sign in or start a 7-day free trial to get started today.

Brought to You by the Writers of American Greetings

We are a team of writers and editors with decades of experience creating happiness, laughter and love for American Greetings. When we’re not writing greeting cards and other celebrations content for the company, we are award-winning authors, bloggers, world travelers, singers, photographers, parents, grandparents and pet owners. Most of us live in Cleveland, Ohio, home to American Greetings Corporate Headquarters for over 100 years.