In the last decades, Western democracies have witnessed an increase in the proportion of voters who make their electoral choice late in the campaign. Consequently, scholars have paid considerable attention to this phenomenon and attempted to identify the factors which influence time of vote decision. This article reviews the literature on the determinants of decision timing. Several studies suggest that women and young citizens are more likely to be late deciders. Besides, party identification has been shown to hasten the electoral decision, whereas attitudinal ambivalence and network cross-pressures have been found to delay the crystallisation of vote intentions. Moreover, previous work reveals that strategic voters decide later than do their sincere counterparts. Special attention is also devoted to the debate on whether the phenomenon of late deciding can be seen as the consequence of a lack of political sophistication or as the product of a high level of political engagement.