The present study examined gender and age patterns of diminutive use in conversations between 32 Spanish-speaking Peruvian mothers and their three- and five-year-old children. Results confirm previous findings concerning both parentsʼ greater use of diminutives with younger children and childrenʼs early acquisition of this complex aspect of morphology. However, findings do not support previous studies on gender differences in parental use of diminutives with young children. Results also revealed that mothersʼ and childrenʼs imitations of their interlocutorsʼ diminutized words promoted their interlocutorsʼ overall diminutive use. This finding highlights the acute sensitivity of both speakers to each othersʼ language and the potential role of imitation in older childrenʼs language development.