The late nineteenth- and early twentieth-century British labour market experienced an influx of female clerical workers. Employers argued that female employment increased opportunities for men to advance; however, most male clerks regarded this expansion of the labour supply as a threat to their pay and status. This article examines the effects of female employment on male clerks using data from Williams Deacon's Bank covering a period 25 years prior to and 25 years subsequent to the initial employment of women. It is shown that, within position, women were substitutes for younger men, but not for senior men. In addition, the employment of women in routine positions allowed the bank to expand its branch network, creating new higher-level positions, which were almost always filled by men.