Most boys stop growing taller by age 16, although muscle development continues into their late teen years. When boys stop growing, it signals the end of puberty. The growth plates close at this time.
Boys hit their growth spurt at about age 11, and they can grow up to 4 inches a year for two years. Most of a boy's growth takes place between ages 12 and 15. Boys experience other physical changes during puberty, including the development of facial, pubic and underarm hair. A boy's voice deepens, his Adam's apple grows larger and his genitals fully develop during this period.