This meta-analysis examined gender differences in self-esteem reported in Japanese research studies. The moderating effects of the ages of the participants in the samples, the years when the research studies were conducted, and the types of translation were also examined. Studies that measured self-esteem of Japanese participants, analyzed by gender, using the Rosenberg Self-Esteem Scale were searched via a comprehensive literature review. Fifty studies published from 1982 to 2013 were collected. The estimated population effect size (Hedges's g) was .17, indicating that males scored slightly higher in self-esteem than females. Analyses of moderating variables revealed that the effect sizes varied according to the ages of the participants and the years when the research studies were conducted. These findings provide an empirical basis for discussion of gender differences in self-esteem among Japanese people.