My son is 20 months old (height 35 inches, weight 27 pounds) and usually carries 2t. I read the reviews and saw that they are a bit small so I bought a size 3t. It fits my son perfectly! The width is perfect but longer in the torso and arms (probably more true to size if your boy is long and narrow in the torso).
Star Wars, Marvel, and Disney Short-Sleeve T-Shirts for Boys from Amazon Essentials
50 Review
π Hanes Boys' Short Sleeve T-shirt Value Pack (3-pack) - Essential Wardrobe Basics
44 Review
Boys' Long-Sleeve Disney Star Wars Marvel T-Shirts by Spotted Zebra
46 Review
The Good Day Lab Clean Shield: Ultimate Comfort and Breathability in Tagless 4-Way Stretch Polo
43 Review
Funny Guy Mugs Tearaway Sweatpants: Playful Boys' Clothing for Fun and Active Days
49 Review
π Boys' Outdoor Climbing Convertible Trousers - Waterproof | Clothing
47 Review
π Bold Pack Sleeve Active Hoodie Sweatshirt Set for Boys' Clothing - Stylish and Comfortable!
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π Fruit of the Loom 6 Pair Cushion Ankle Boys' Clothing: Comfy and Stylish Selection for Active Boys
57 Review