The mean age at marriage of Iranian women increased by three years between the mid-1980s and 2000 during a period of great socio-economic change, particularly affecting the 1971–1975 and 1976–1980 birth cohorts. This paper analyses the marriage timing and life course experience of these cohorts of women and highlights the contribution that ethnicity and changes in the socio-economic context made to the sharp marriage delay experienced by the 1976–1980 birth cohort. A discrete time hazard model is applied to the 2000 Iran Demographic and Health Survey data, which are linked to a range of time-varying district-level contextual variables created from the 1986 and 1996 Iranian censuses. The findings suggest that the marriage postponement experienced by the younger birth cohort is related to improvements in women's education and can partly be explained by the increased opportunity costs of marriage, which resulted from limited access to education after marriage. The findings also suggest that differences in marriage timing between areas predominated by certain ethnic groups became less evident for the younger birth cohort.