Abstract The Japanese term, shakaijin, refers to becoming a social adult, and locates the transition to adulthood in leaving school/university and entering an employment relation. In this paper we explore the role of company socialization in producing social adults. Company socialization is explored through a case study of a securities company, and an additional study of a large bank. New employee training programs are a central socializing event, and bridge the transition from school/university-to-work. In this study, events prior to and subsequent to new employee training arc also shown to play key roles in company socialization. Recruitment practices socialize as well as screen job applicants. Regular personal assessments continue socialization throughout the working life cycle. Based on the analyses of socialization in recruitment, training and assessment, two aspects of company socialization in Japan are emphasized. First, company socialization involves gender socialization. Male employees are the main subjects of company socialization, and their induction to social adulthood seeks to generate commitment and social integration to company life. Social adulthood of female employees is defined in connection with future familial roles rather than commitment to work. Second, the meaning of social adulthood for men is fused with acceptance of management goals. Company socialization attempts to align individual attitudes and behaviors with company goals.