Nowadays, throughout Morocco a dynamic process of modernization is embracing fertility and nuptial behaviors, family planning, contraceptive use, the role and status of women in the family as well as in society, and political orientations, challenging the foundations of the patriarchal system. The progression from second to third birth is a crucial step in fertility change during fertility transition since the reduction especially in third and higher-order births maintains fertility decline. For these reasons, the study aims at analyzing the main determinants of third-birth intensities, applying an eventhistory analysis to the most recent retrospective Moroccan survey data. The findings show that differences among social groups still persist: higher risks of giving birth to the third child characterize women with a lower educational level and experiencing a rural background. Nevertheless, within the framework of the ongoing process of modernization in the country and geared to promote women’s status, all segments of the population are rapidly changing their fertility behaviors. Third-birth fertility appears to decline monotonically for all educational groups. This suggests that the general drop in Morocco is due to general period effects that affect all strata of the population and various composition effects where increasingly large groups join the socio-economic groups that have the lowest fertility. Moreover, the analysis shows no consistent or clear evidence of sex preference among Moroccan mothers in the progression to the third child. There seems to be a slight aversion towards having two girls; however, this tendency admittedly is not statistically significant.