The final part of the formation of a mature sperm cell, in which the round, early spermatid (already with a haploid number of chromosomes) loses its round shape to acquire the features of the mature, elongated spermatozoon. Contrast with spermatogenesis, which encompasses spermiogenesis as it's completed.

Development of a sperm cell, in the tubules of the testes (the testicular tubules), from spermatogonium and spermatocyte to spermatozoon (the last part of this process, from spermatid to spermatozoon, is called spermiogenesis). The process of spermatogenesis takes 56 days. At any one location in a tubule there are cells at four different stages of maturity, so mature sperm are released from a particular location into the lumen of the testicular tubules every 14 days. A systematic interruption of spermatogenesis results in azoospermia and is called maturation arrest.