This study explores the significant role played by married female substitute teachers, who have become in effect a sort of "reserve army," a reserve labor force in Taiwan's school system. Compared with previous research, which has ignored the work conditions and experiences of these substitute teachers, this study was based on the belief that the patriarchy constrains women's career development: especially that of married women whose opportunities are interrupted and curtailed by marriage and child-care tasks. Focusing on the issues of job opportunities, human capital, and gender, the researchers compare the part-time short-term substitute teachers' work experiences with those of long-term substitute teachers. It is concluded that more attention needs to be given to the status of substitute teachers and the general trend toward the feminization of school teaching in Taiwan.