Boys stop growing at the end of puberty, which tends to be around age 16 for most boys. Growth stops when the growth plates of the bones fuse, which is triggered by hormonal changes at the end of puberty.
Puberty is a time during which a boy's body becomes sexually mature. Generally beginning between the ages of 10 and 13, puberty in boys is marked by the appearance of pubic hair, deepening of the voice, enlargement of the Adam's apple and overall rapid growth. Most boys begin a growth spurt between the ages of 12 and 15. This growth spurt lasts about two years on average; boys grow about 4 inches per year during this period. Although bone growth stops at the end of puberty, many boys do continue to put in more muscle in the years following puberty. As a result, they continue to look broader each year as they mature into adults.
Although a boy's final height is determined partially by genetics, other factors are involved, too. Good nutrition, plenty of sleep and regular exercise ensure that a boy reaches his full height potential. It is common for a boy to be either taller or shorter than his classmates during his teen years. This generally means that the boy is maturing at a different rate than his peers.