The purpose of this study was to examine the relation between children's me
tacognitive private speech and their mastery motivation when working on 3 a
ge-appropriate but challenging tasks. Metacognitive private speech was defi
ned as children's nonsocial utterances that reflected heightened awareness
and regulation of their own thinking. Mastery motivation referred to the yo
ung children's disposition to work for a challenging goal. A total of 31 pr
eschoolers, aged 3 to 5 years, participated in this study. The proportion o
f metacognitive private speech for each task to children's overall private
talk across the 3 tasks was analyzed. Results for the 3 tasks indicated tha
t children's metacognitive private speech was correlated with their mastery
behavior. Specifically, young children who engaged in higher proportion of
metacognitive private speech were more likely to strive to complete the ch
allenging tasks or work without the direct assistance of an adult. Implicat
ions of these findings for research and education are considered.