This project website is designed to provide a full description of the materials and Rscript used in the analysis of our study. If you have any questions, please don't hesitate to contact the main author (Jacqueline Wong: wong@essb.eur.nl). Abstract. Online learning environments demand learners to self-regulate their learning but many learners are poor at self-regulated learning (SRL). In this study, two experiments were conducted to examine the effect of two SRL supports, i.e., guiding goal setting and planning using an approach known as mental contrasting and implementation intentions [MCII] and prompting SRL using videos, on motivation in the form of task value and self-efficacy, SRL in the form of persistence, task strategies, self-evaluation, and self-satisfaction, student engagement, and performance. In Experiment 1, a two (MCII, no MCII) by two (prompt, no prompt) between-subjects experiment was conducted in a video-based learning environment. Results showed that learners who completed the MCII had sustained task value and higher persistence than learners who did not receive the MCII. Experiment 2 was conducted in five Massive Open Online Courses where we compared three conditions: MCII, goal only, and control. Results showed that there were no significant differences in SRL activities, course engagement and performance, and goal attainment among the three conditions. Collectively, the results suggest that the task duration in which learners’ goals can be attained (e.g., within one short session or over multiple weeks) might influence the effectiveness of MCII.