Utilizing data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development's Study of Early Child Care and Youth Development, we investigated mothers' talk about mental states during play with their 24-month-old children as a mechanism though which infant-mother attachment was associated with children's later friendship quality. A series of repeated measures analyses of covariance indicated that a secure versus avoidant or disorganized infant-mother attachment was associated with more maternal talk about cognitions (but not emotions or desires) at 24 months. Latent growth curve models tested within a structural equation modeling framework revealed indirect effects of infant-mother attachment on observed and mother-reported positive friendship interaction at 54 months and decreases in mother-reported negative friendship interaction from 54 months to 1st grade via maternal cognitive talk at 24 months. (Contains 3 footnotes, 4 tables, and 4 figures.)