Although differences in female labour force participation between Southern European countries date back to the seventies, the literature addressing the phenomenon is quite scarce. The fact that participation rates in Portugal are 10 to 15 percentage points higher than elsewhere in Southern Europe has been simply considered a distinctive characteristic of the Portuguese labour market. However, the question remains: why is female labour force participation so high in Portugal, relative to all other Southern European countries? It was lack of answers in the literature that has led to the following analysis. An initial investigation of females’ individuals characteristics has suggested that these play a modest role in accounting for cross country differences, despite the interesting results concerning the correlations between marriage and fertility, and female labour force participation. The subsequent analysis of a set of labour market features which although be yond the control of females' individual decisions, would be related to their labour force participation, has allowed to conclude that there are no common trends or stylized facts associating female labour force participation with occupational segregation, gender wage differentials, part-time and other atypical forms of work, or with public sector work. Nevertheless, there is still a scope for some or all of these labour market features to be relevant for subgroups of Southern European countries. Finally, the importance of fertility was evaluated taking into account its potential endogeneity relative to labour market decisions. The approach followed has relied on females’ contraceptive behaviour to construct instruments for fertility. The results obtained, indicate that child penalties, in terms of female labour force participation, are likely to be higher in Spain than in Portugal, suggesting that fertility may play an important role in accounting for cross country differences in participation rates. The fact that no definite explanation has been reached concerning cross country differences in female labour force participation in Southern Europe, leaves the research agenda on the topic open. There has been an important trade-off between comparability between countries and the depth of the analysis pursued. Nevertheless, other potential explanations could and should be considered, namely, labour market institutions, as well as other empirical approaches, for instance, based on data also from the employer’s side.