Activity and employment rates for immigrant women in many industrialized countries display a great variability across national groups. The aim of this paper is to assess whether this well-known fact is due to a voluntary decision (i.e. large reservation wages by the immigrants) or to an involuntary process in that the labour market evaluation of their skills is low. This is done by estimating the reservation wages for each individual in the dataset. Our results show that low activity and employment rates for certain national groups are not associated with high reservation wages. This implies that low participation should not be interpreted as a voluntary decision.