This study investigates how young English as a foreign language (EFL) learners from Chinese, Spanish, and Polish mother tongue backgrounds use interactional metadiscourse in descriptive and argumentative English essays by drawing data from the ICCI corpus. The quantitative and qualitative analyses show that (i) there are significant differences among the three groups of EFL learners in the use of boosters, attitude markers, self-mentions, and engagement markers; and (ii) there are significant differences between the descriptive essays and the argumentative essays in the use of hedges and self-mentions. Discussion of the results is related to intergroup homogeneity and heterogeneity in the use of metadiscourse and the influences of essay types as well as topics/prompts. Pedagogical implications are provided for teaching interactional metadiscursive resources to young EFL learners from different mother tongue backgrounds and in relation to descriptive and argumentative writing.