This paper examines the changing nature of attitudes toward and reports of sexual harassment using data for 1978–94 drawn from the U.S. Merit Systems Protection Board (USMSPB) of the U.S. federal government. The authors find that although unwanted sexual behavior reported by federal government employees changed only slightly in overall incidence over the period, its pattern changed noticeably. Unwanted sexual attention by supervisors, for example, declined in incidence; crude and offensive behavior by co-workers increased; and the likelihood that harassment would occur only once (rather than repeatedly) increased. Employees’ attitudes toward sexual harassment changed markedly, with a dramatically increased willingness to define unwanted sexual behavior as sexual harassment. This trend appears to have been due not to changes in employees’ demographic, human capital, and job characteristics, but rather to structural changes in their views of what constitutes sexual harassment.