The present study explores the impact of different levels of competition involved in gamified learning on adult e-learners' intrinsic motivation, learning engagement, and language learning performance. One hundred and twenty participants were evenly and randomly assigned to two groups. A gamified learning procedure with a higher level of competition was applied in the experimental group, while a similar gamified learning process which was less competitive was assigned to the reference group. A pretest, a posttest, and three questionnaires concerning the participants' perceived competition, intrinsic motivation, and perceived learning engagement were employed as the instruments. The results showed that the higher-level competition exerted a more positive impact on the learners' intrinsic motivation, learning engagement and language learning performance than the lower-level one. The results suggest that gamified learning involving appropriate competition levels could be considered for generating efficient learning outcomes.