Sex development is one of the hot spots in evolutionary biology. It mainly includes sex determination and sex differentiation. There are two mechanisms of sex determination in vertebrates, including genotypic sex determination (GSD) and environmental sex determination (ESD). For amphibians, GSD is a primary mechanism of sex determination, in which the sex is determined by sex chromosomes of bisexual gametes at fertilization, but there is growing evidence showing that the sex is also modified by ambient temperature and sex hormone. The phenomenon of sex reversal generally appears in amphibians, and the physiological and molecular mechanisms have been reported. Here, we summarized the physiological and molecular mechanisms of sex determination and sex differentiation in amphibians, with the focus on the influences of sexrelated genes on sex determination, the effects of temperature and sex hormone on sex differentiation and expression of sexrelated genes. Efforts were made to point out the priority in further studies of sex development in amphibians.