This study examined stability of maternal sensitivity and efficacy of a Q-sort measure of maternal sensitivity across time and context. Two versions of the maternal behavior Q-set (MBQS) were employed, first during the Strange Situation Procedure (SSP) and second at home, 2.5 years later based on an available subsample. Findings revealed that the MBQS scores assessed at two time points in two contexts were significantly correlated, showing the stability of maternal sensitivity of the subsample over a time period of 2.5 years. The MBQS scores assigned to mothers of preschoolers were also significantly correlated with their children's early interactive behavioural scores given during the SSP. The current findings further support validating the consistency, the versatility and the efficacy of the MBQS as a sound measure of maternal sensitivity. Copyright © 2013 John Wiley & Sons, Ltd.