What is a good pant size for a 13 year old girl?

A good pant size for a 13-year-old girl can vary widely depending on her height, weight, and body shape. Generally, sizes range from 0 to 16 in juniors or 10 to 18 in girls' sizing. It's best to measure her waist and hips and consult a size chart for the specific brand, as sizing can differ between manufacturers. Ultimately, comfort and fit should be the priority when choosing pants.