The purpose of the study was to use the Theory of Planned Behaviour (TPB) to identify the underlying beliefs that impact online learning behaviours of graduate students at the Faculty of Educational Studies, University of Education, Winneba, Ghana following the sudden outbreak of COVID-19, which led to national lockdowns and closure of schools. The article reports attitudinal, normative and control beliefs of graduate students to accept learning management system (LMS) for online learning and also establishes which of the three beliefs influenced their readiness for online learning. One hundred and sixty-four graduate students of the Faculty of Educational Studies, University of Education, Winneba, completed questionnaire hosted on Google Form. Data were analysed using frequencies, percentages, means, standard deviations, MANOVA, Pearson's moment correlation and ordinary least squares multiple regression. The findings revealed that perceived usefulness of the LMS for online learning and perceived lecturer readiness to use LMS as well as students’ learning autonomy combined to influence students’ willingness to accept LMS for online learning. The study recommended that the university authority should intensify ICT training and usage among students and staff to sustain the use of LMS for online teaching and learning. The researchers should also extend the study to the undergraduate students who constitute the largest proportion of student population of the university.