Self-regulated learning (SRL) plays a crucial role in online learning success. However, students inevitably encounter off-task thoughts (mind wandering or task-related interference) that can disrupt the learning process. Although SRL and off-task thoughts have been studied independently, their interaction has not been extensively explored. This research project investigates the relationship between SRL and off-task thoughts in the context of learning from videos. A multi-method approach will be employed, comprising a conceptual paper, meta-analyses, case study, two experiments, and comparative analysis. The conceptual paper will present a model illustrating how off-task thoughts may trigger reactive self-regulation during learning. The meta-analyses will synthesize findings on the occurrence and impact of task-related interference and off-task thoughts. A naturalistic case study and two controlled experiments will collect self-caught thought reports during actual and simulated video learning, respectively. The case study will explore whether students rewind videos after mind wandering. The experiments will test whether the anticipation of learning activities at pauses in the video leads to increased awareness of off-task thoughts and whether rewinding a video following off-task thoughts balances out the negative effect of mind wandering. Comparing the case study and both experiment results will assess the generalizability of findings across contexts. A comparative analysis will also examine the association between SRL and off-task thought frequency in naturalistic and controlled settings. This research project aims to provide theoretical and empirical insights into the interaction between off-task thoughts and SRL when learning from videos.