I bought a small t-shirt for my 5.5 year old to wear with my custom fleece pajama bottoms that I made (although I didn't know enough skill to sew a shirt). It suits her in length, but otherwise it fits her quite well, ie not too wide and not loose. She likes the fit, the shirt is soft, washes well and doesn't pill.
Amazon Brand Sleeveless Chambray Multi Dots Girls' Clothing
62 Review
Adorable TABNIX Toddler Little Girlsβ Short Sleeve T-Shirts: 4-Pack Graphic Cotton Tops for Size 2-7 Years
44 Review
Kid Nation Short Sleeve Crew Neck Heather Girls' Clothing for Tops, Tees & Blouses
52 Review
Spotted Zebra Girls' Short-Sleeve Flutter T-Shirts: Amazon Brand for Fashionable Kids
43 Review