This mixed method study aims to address the lack of self-regulation in primary school students through providing self-regulation training with prompts and modeling in virtual flipped classroom (VFC). A four-week training was integrated into an extra-curricular program of Chinese speech with prompts or modeling embedded in pre-class videos. The study examines to what extent and how prompts and modeling affect students' self-regulation and learning outcome. Forty-two primary school students from Grades 4 to 6 were randomly assigned into the prompt group and the modeling group. Both groups had not received self-regulation training before and did not show significant difference in the pre-test of self-regulation and the ability of speaking Chinese. The study collects multiple types of data including questionnaires, students' notes, observations, interviews, and speaking tests. The study is innovative as it directly compares the effectiveness of modeling and prompts on enhancing students' self-regulation. The results show that both prompts and modeling are effective in enhancing students' self-regulation and learning outcome with modeling having an edge over prompts. The students and their parents expressed positive views towards self-regulation training in the program. This study provides several implications for practitioners on how to cultivate students' self-regulation.