Both boys and girls stop growing in height at the end of puberty. This makes the age slightly different for girls and boys; girls typically reach the end of puberty around age 17 to 18, and boys at the age of 18 to 20.
It is possible for a male to not reach his full height until his early 20s. Some boys will remain short in stature even at the age of 16 or 17. Some factors that affect height include heredity and illnesses. Nutrition also plays an important factor in how tall someone will be, according to WebMD. A good way to determine how tall a child will be is to map a growth chart as they begin to grow.