As English massive open online courses (MOOCs) continue to expand in China, learners benefit from flexible access to language learning but also face risks to their psychological well-being due to limited interaction and high autonomy. This study aims to examine the extent to which self-regulated learning strategies (SRLS) predict five dimensions of well-being: Positive Emotion, Engagement, Relationships, Meaning, and Accomplishment, among 566 Chinese university students learning English through MOOCs. Guided by Seligman’s PERMA model and social cognitive theory, the study examines how SRLS predict well-being and also explores learners’ SRLS and well-being levels, as well as whether these levels differ by gender and academic year. A quantitative design was employed, and data were collected via online surveys and analyzed using structural equation modeling (SEM). Participants reported moderate levels of SRLS use and moderately high levels of well-being, with the highest scores in study environment management and Accomplishment. SEM revealed that SRLS significantly and positively predicted all five PERMA dimensions, especially Accomplishment and Engagement. However, gender and academic year did not show any significant influence on SRLS use or well-being outcomes. The findings show that SRLS contribute to psychological well-being and flourishing, and offer valuable guidance for creating English MOOCs that are both emotionally supportive and autonomy-oriented.