Objective: This study examined associations among Korean immigrant mothers’ use of praise and encouragement, their acculturation, their children’s socioemotional and behavioral difficulties, and the moderating role of child gender and age. Design: One hundred and twenty Korean immigrant mothers in the United States and their preschool children participated. Maternal praise and encouragement were observed during free-play interactions. Mothers reported their acculturation level, and teachers reported on children’s difficulties. Results: Mothers used process praise most frequently. Higher maternal American acculturation was associated with more use of person and other praise. Higher Korean acculturation was associated with greater use of person praise among younger children, but less use of person praise among older children. Mothers higher in American acculturation used more encouragement with older children only. Maternal encouragement was associated with fewer child difficulties. Conclusion: Korean mothers’ acculturation impacted their use of praise and encouragement, and maternal encouragement may be important for decreasing children’s difficulties.