Your brother’s getting married, and you’re staring at a blank page wondering how to capture years of shared memories, inside jokes, and genuine love in a single letter.
Whether you’re the older sibling who changed his diapers or the younger one who tagged along everywhere, finding the right words can feel impossible.
Here are seven letter templates that hit different emotional notes—from heartfelt and sentimental to funny and irreverent. Pick one that matches your relationship, swap in your own stories, and you’ll have something that’ll make him tear up (in a good way).
1. The Sentimental Classic
“Dear [Brother’s Name],
I’ve been trying to write this letter for weeks, and every time I start, I get stuck thinking about that kid who used to follow me around asking a million questions. Now look at you—about to marry the love of your life and start this incredible new chapter.
Watching you with [Partner’s Name] reminds me why I always believed you’d find something special. You’ve got this way of making people feel like they’re the most important person in the room, and seeing how she lights up around you tells me everything I need to know about this match.
I remember when you first told me about her, how your whole face changed when you said her name. That’s when I knew this was different. You’ve always been the one who loves with his whole heart, never holding anything back, and she clearly sees that beautiful quality in you that we’ve all been lucky enough to witness.
Today isn’t just about gaining a sister-in-law (though I’m pretty excited about that). It’s about watching my brother step into the life he’s always deserved.
Marriage isn’t always easy—trust me, there will be days when you’ll wonder why anyone thought combining two completely different humans was a good idea. But you two have something solid, something real.
Take care of each other. Be patient when she loads the dishwasher wrong, and remember that being right isn’t always worth being alone on the couch.
Love you, brother.
[Your Name]”
This template works best if you’re naturally sentimental and have a close relationship with your brother. It acknowledges the transition from childhood to marriage while keeping things warm and genuine.
The beauty of this approach is that it doesn’t try to be funny or clever—it just speaks from the heart. You can easily customize it by adding specific memories or adjusting the tone to match how you actually talk to each other.
2. The Funny Roast (With Love)
“Dear [Brother’s Name],
Well, someone actually agreed to marry you. I’m still processing this miracle, but [Partner’s Name] seems to have her head screwed on straight about everything else, so I’m choosing to trust her judgment here.
I’ve spent [number] years watching you perfect the art of leaving dishes in the sink ‘to soak’ and wearing the same lucky shirt until it could practically walk itself to the laundry room.
Somehow, she finds this charming. This woman is either a saint or has a very specific type, and either way, you hit the jackpot.
Remember when you practiced asking her out in the mirror for three hours? Or when you spent an entire paycheck on that first anniversary dinner and then couldn’t afford gas money? She stuck around through all of it, which proves she’s not just marrying you for your devastating good looks and sparkling personality.
But here’s the thing—underneath all that weird stuff you do (and trust me, the list is long), you’re actually a pretty decent human. You’re loyal, you’re kind, and you make people laugh even when they’re trying to stay mad at you. [Partner’s Name] sees all of that, plus she’s apparently immune to your terrible dad jokes.
So here’s my advice: keep being the goofball she fell in love with, but maybe invest in some actual laundry detergent. And remember, happy wife, happy life isn’t just a saying—it’s a survival strategy.
Congratulations, you lucky bastard.
[Your Name]”
This template is perfect if your relationship thrives on good-natured teasing and inside jokes. The humor keeps things light while still expressing genuine affection and respect for the relationship.
The key is balancing the roasting with real sentiment. You want him laughing, not wondering if you actually like his partner or support the marriage.
3. The Protective Older Sibling
“Dear [Brother’s Name],
I still remember the day Mom and Dad brought you home from the hospital. You were this tiny, wrinkled little thing, and I immediately appointed myself your official protector. Today, I’m officially passing that job to someone much more qualified.
[Partner’s Name] loves you in a way that makes my heart happy and my job as big brother a lot easier. I’ve watched her stand by you through job changes, family drama, and that unfortunate phase when you thought you were going to be a professional gamer. She didn’t just stick around—she believed in you.
You’ve grown into a man I’m genuinely proud to call my brother. You’re thoughtful, hardworking, and you’ve got this quiet strength that I think you inherited from Dad. More importantly, you’ve learned how to love someone well, which isn’t something they teach you in school.
I know I’ve been overprotective sometimes. Okay, maybe more than sometimes. But watching you two together has taught me that the best protection I can offer is stepping back and letting you build something beautiful with the right person. And she is absolutely the right person.
Marriage is going to challenge you in ways you can’t imagine yet. There will be times when you’ll need to choose between being right and being kind—always choose kind. Listen more than you talk, especially during arguments, and never forget that you’re on the same team.
I’m not losing a brother today; I’m gaining a sister and watching you become the man you were always meant to be.
Love and respect,
[Your Name]”
This template captures that unique dynamic between older siblings who feel responsible for their younger brother’s wellbeing. It acknowledges the transition of roles while maintaining that protective love.
The tone is more serious and reflective, which works well if you have a relationship built on mutual respect and shared family experiences. It also gives practical advice without being preachy.
4. The Younger Sibling’s Perspective
“Dear [Brother’s Name],
You’ve been my built-in best friend since day one, even when I was being an annoying little sister/brother who just wanted to tag along everywhere. Thanks for never making me feel like I was too young or too much trouble—well, most of the time anyway.
I’ve learned so much about relationships just from watching you and [Partner’s Name] together. You two actually like each other, which sounds obvious but isn’t always a given.
You laugh at each other’s stories even when you’ve heard them a hundred times, and you both get genuinely excited about the other person’s wins.
Growing up, I always thought you were pretty cool (don’t let it go to your head), but seeing you as someone’s partner has shown me sides of you I never knew existed.
You’re patient in ways I never was, thoughtful about things that would never occur to me, and you’ve got this way of making [Partner’s Name] feel absolutely cherished.
I used to worry about who would be good enough for my big brother. Turns out, the question was whether my big brother would be good enough for someone as amazing as [Partner’s Name]. Lucky for all of us, you stepped up your game.
As you start this new adventure, remember that your annoying little sibling is always here if you need anything—advice, a listening ear, or someone to tell you when you’re being an idiot. That’s what family is for.
Here’s to love, laughter, and [Partner’s Name] finally understanding all our weird family references.
All my love,
[Your Name]”
This perspective captures the unique admiration younger siblings often feel for their older brothers, combined with the joy of seeing them truly happy. It’s affectionate without being overly sentimental.
The template acknowledges how the brother has been a role model while also recognizing his growth as a partner. It maintains that sibling bond while welcoming the new family member.
5. The Long-Distance/Reconnecting Sibling
“Dear [Brother’s Name],
I know we haven’t been as close as we used to be—life, distance, and our own stubborn personalities have gotten in the way more than they should have. But watching you prepare for this day has reminded me of all the reasons I’m proud to be your brother/sister.
Even from far away, I can see how happy [Partner’s Name] makes you. The way you talk about her, the way your whole energy changes when she’s around—it’s obvious she brings out the best in you. And from what I’ve seen, you do the same for her.
I regret that I haven’t been around as much as I should have been during your relationship. I missed some of the milestones, some of the stories, some of the moments that brought you to this day. But I’m here now, and I want you to know that distance has never changed how much I care about your happiness.
You’ve always been someone who loves deeply and commits fully. I remember that about you from when we were kids—you never did anything halfway. Seeing you choose [Partner’s Name] as your person tells me everything I need to know about her character and your future together.
I promise to be better about staying connected, about being present for the big moments and the small ones. Your marriage is a fresh start for all of us, and I want to be the sibling you deserve—not just today, but going forward.
Congratulations to both of you. I can’t wait to see what you build together.
With love and renewed commitment to family,
[Your Name]”
This template is honest about distance or strained relationships while focusing on the positive and making commitments for the future. It acknowledges past shortcomings without dwelling on them.
The tone is mature and reflective, perfect for siblings who have grown apart due to circumstances rather than conflict. It offers hope for renewed closeness while celebrating the present moment.
6. The Practical/Advice-Giving Sibling
“Dear [Brother’s Name],
You’re probably expecting some mushy speech about how proud I am or how much you’ve grown. Don’t worry—I’ll get to that. But first, let me share some things I’ve learned about marriage that nobody tells you in the fairy tales.
[Partner’s Name] is going to have bad days when nothing you do is right, and you’re going to have days when you wonder why she can’t just read your mind. This is normal.
The secret is remembering that you’re both doing your best with the information you have, and sometimes the best thing you can do is order pizza and start over tomorrow.
You’re both going to change over the years—hopefully in ways that make you more interesting to each other, not less. Don’t try to keep each other exactly the same as you are today. Grow together, not apart, and check in regularly to make sure you’re still heading in the same direction.
Now for the mushy part: I am genuinely proud of the man you’ve become. You’re thoughtful, dependable, and you’ve chosen a partner who matches your energy and complements your strengths.
[Partner’s Name] isn’t just beautiful and smart—she gets your sense of humor and doesn’t try to change the weird things that make you you.
Marriage isn’t about finding someone you can live with; it’s about finding someone you can’t imagine living without. Based on how you two look at each other, I’d say you figured that out already.
Be patient, be kind, and don’t forget to have fun together.
Love and practical wisdom,
[Your Name]”
This template balances genuine emotion with practical advice, perfect for siblings who have a relationship built on mutual respect and shared experiences. It offers real wisdom without being preachy.
The approach works well if you’re married yourself or have observed enough relationships to offer meaningful insights. It shows you take their marriage seriously while keeping things grounded and realistic.
7. The Simple and Heartfelt
“Dear [Brother’s Name],
Some people spend their whole lives looking for what you and [Partner’s Name] have found in each other. You’re lucky, but more than that, you’re smart enough to recognize it and brave enough to commit to it.
I love watching you two together. There’s something easy and natural about your relationship that makes everyone around you believe in love a little bit more. You support each other, you make each other laugh, and you’ve built something solid and real.
You’ve always been someone who gives his all to the people he loves. I’ve seen it in how you care for our family, how you show up for your friends, and especially in how you love [Partner’s Name]. She’s getting someone truly special, and I know she sees that.
Marriage is going to be an adventure—sometimes challenging, always rewarding, and hopefully filled with more laughter than tears.
You two have what it takes to build something beautiful together. You have love, respect, shared values, and the kind of friendship that makes the hard days easier and the good days even better.
I’m excited to see what your life looks like in five years, ten years, and beyond. I’m excited to watch you become parents someday if that’s what you choose, to celebrate anniversaries, and to see how your love story continues to unfold.
Today is just the beginning. Enjoy every moment.
All my love,
[Your Name]”
This template is perfect when you want to keep things genuine and straightforward without being overly complex or trying too hard to be funny or profound. It focuses on the relationship and the future.
The beauty of this approach is its simplicity and sincerity. It works for any sibling dynamic and can be easily personalized with specific details about their relationship or your shared experiences.
How to Write Your Own Letter
Start with your authentic voice, not what you think a wedding letter should sound like. If you’re naturally funny, be funny. If you’re more serious, embrace that. Your brother knows who you are—don’t suddenly become someone else because it’s a formal occasion.
Think about specific memories or qualities that make your relationship unique.
Maybe it’s how he always shared his Halloween candy, or how he taught you to ride a bike, or that time he drove four hours to help you move. These details make the letter personal and meaningful rather than generic.
Consider what you genuinely want him to know. Are you proud of how he’s grown? Grateful for his friendship? Excited about his future? Happy that he found love? Start with those real feelings and build from there.
Don’t worry about being perfect or profound. The most touching letters are often the most honest ones—the ones that capture real relationships with all their complexity, humor, and love.
Your brother will treasure your words because they came from you, not because they sound like they belong in a movie.
Keep it conversational. Write like you’re talking to him, not delivering a speech to strangers.
Use the same tone and language you’d use if you were sitting across from each other at coffee. That authenticity will make your letter stand out from all the formal well-wishes he’ll receive.
Finally, don’t overthink the length or structure. Some of the most meaningful letters are short and sweet, while others ramble on for pages. What matters is that your words come from a place of genuine love and celebration for this new chapter in his life.