Objectives The COVID-19 pandemic has brought a significant impact on people’s behaviour and lifestyles. Limited research has been conducted on the impact of COVID-19 on Malaysian university students’ lifestyle modifications. This study aims to identify the impact of COVID-19 on dietary intake, sleeping patterns and physical activity levels among Malaysian university students. Methods A total of 261 university students were recruited. Sociodemographic and anthropometric data were collected. Dietary intake was assessed using PLifeCOVID-19 questionnaire, sleep quality was assessed using Pittsburgh Sleep Quality Index Questionnaire (PSQI) while physical activity level was assessed using International Physical Activity Questionnaire-Short Forms (IPAQ-SF). SPSS was used to perform statistical analysis. Results 30.7% of the participants adhered to the unhealthy dietary pattern, 48.7% had poor quality of sleep and 59.4% engaged in low physical activity levels during the pandemic. Unhealthy dietary pattern was significantly associated with a lower IPAQ category (p=0.013), and increased time spent sitting (p=0.027) during the pandemic. Participants being underweight before the pandemic (aOR=2.472, 95% CI=1.358–4.499), increased takeaway meal consumption (aOR=1.899, 95% CI=1.042–3.461), increased snacking between meals consumption (aOR=2.989, 95% CI=1.653–5.404) and engaged in a low level of physical activity during pandemic (aOR=1.935, 95% CI=1.028–3.643) were the predictors of unhealthy dietary pattern. Conclusions The university students’ dietary intake, sleeping patterns, and physical activity levels were impacted in different ways during the pandemic. Strategies and interventions should be developed and implemented to improve the dietary intake and lifestyle of the students.