This study examines the effects of monologic and dialogic task sequences on incidental vocabulary learning among 115 students in four intact classes of a Chinese vocational high school. Twenty vocabulary items including words, phrases and fixed expressions ranging from high to low frequency levels were targeted. Students were required to complete meaning-focused oral tasks by applying different sequence combinations within three weeks. Vocabulary meaning and application, involving meaning recognition, meaning recall, and form recall, were assessed using pre-and post-tests. The results confirmed the efficacy of meaning-focused oral tasks in promoting incidental vocabulary learning and showed that different sequence combinations can lead to varying learning outcomes. The findings suggest that incidental vocabulary meaning learning is more dependent on meaning-focused tasks and less influenced by task sequences. On the other hand, vocabulary application learning is more influenced by task sequences, indicating that a balance between cognitive load and involvement load may have a positive effect on application learning. Pedagogically, the simple-complex-complex sequence in monologic tasks and the complex-simple-complex sequence in dialogic tasks were found to result in significantly worse performance than other sequence combinations for both vocabulary meaning and application learning.