Self-regulated learning is critical for success in online learning. However, students inevitably experience off-task thoughts (mind wandering) that can disrupt learning. Although these two factors have been studied independently, the relationship between self-regulated learning and off-task thoughts has not been studied extensively. This research explores the relationship between self-regulated learning and off-task thoughts while learning online from a video. A mixed methods approach combines meta-analysis, a case study, an experiment, and comparative analysis to investigate off-task thought frequency and its influence on self- regulation processes. A conceptual paper will present a model of how off-task thoughts may prompt reactive self-regulation during learning. Meta-analysis will synthesize the occurrence and impact of task-related interference. A naturalistic case study and controlled experiment will gather self-caught thought reports during actual and simulated video learning. Comparing results will assess generalizability across contexts. This research will provide theoretical and empirical insights into the relationship between off-task thoughts and self-regulated learning when learning from videos.