boy jumping on a trampoline with a 4th birthday tshirt - Four Ever Wild - The Joyful Rebel

For Personalised Birthday Shirts, Birthday Girl T-Shirts, and Birthday Boy T-Shirts

At The Joyful Rebel, we know how important it is for your child to feel comfortable and confident on their big day. That’s why we’ve created this helpful guide to make sure your personalised birthday t-shirt fits just right—whether you're shopping for a birthday boy t-shirt, birthday girl t-shirt, or our popular children’s birthday t-shirts.

Our Sizing: Relaxed & Comfy

Our t-shirts are designed with a relaxed fit, especially in length. This means they tend to run slightly larger than standard high street sizes—great for growing kids or those who prefer a bit more room to move and play during parties.


✅ Tip: If you're between sizes or prefer a closer fit, consider sizing down.

How to Measure Your T-Shirt?

To find the best size, grab a t-shirt that fits well and follow these simple steps:

  1. Lay out on a smooth surface.
  2. Chest: Measure from armpit to armpit.
  3. Length: Measure from the top of the collar (at the neckline) straight down to the bottom hem.

Once you have these measurements, compare them to our size chart to choose the best match.

T-shirt sizes for The Joyful Rebel tops

Measure the right size

Our children’s birthday t-shirts are made to be worn during exciting, fun-filled parties—whether that means cake-eating, jumping, or running around in a soft play centre.

That’s why getting the right size is key to making sure your child stays comfy all day.

Every personalised birthday t-shirt is made to order, we cannot offer returns or exchanges for sizing issues.

Frequently Asked Questions

Can I customise the design on the birthday t shirts?

Yes, we offer a variety of customisation options for our birthday t shirts, including the ability to add your child's name or age.

Do you offer discounts for bulk orders of birthday t shirts?

We may be able to offer discounts for large orders and wholesale. Please contact us for more information.

Do you ship your personalised birthday tshirts internationally?

Currently, we only ship within the United Kingdom. However, check out my Etsy store - we offer international delivery from there.

Take a look at our blog!

View all
1 3
View all