We report two studies that investigated the continuity and stability of maternal mind-mindedness (MM) across different times, contexts, and relationships, and also examined child communicative development in the second year of life. Three main findings emerged. First, the percentages of appropriate mind-related comments (AMRC) decreased between 16 and 20 months, while the children's production of words and gestures increased. Second, mothers addressed more AMRC to secondborns than to firstborns, when both were tested at the same age (16 months), but firstborns produced more gestures than secondborns (both at 16 and 20 months). Third, unlike mothers' general language measures and child communicative skills, MM was temporally, contextually, and relationally unstable. Overall, these findings suggest caution in considering MM as a stable behavioural trait. It appears, instead, that the production of AMRC may vary according to a wide range of factors.