question: AIMS: To evaluate health-promoting behaviour among Saudi adults in the Jazan region during the COVID-19 pandemic. DESIGN: Cross-sectional study design. METHODS: Saudi adults (N = 305) completed an online survey from 23 April to 5 July 2020. The survey comprised demographic/social factors, COVID-19 pandemic-related factors and the Health-Promoting Lifestyle Profile-II. RESULTS: On average, participants reported participating in health-promoting behaviour 'sometimes'. Only years of education was associated with participation in health-promoting behaviour generally. Nutritional behaviours were positively correlated with sex, age and having a job before and/or after the pandemic and negatively correlated with the number of people in the household. Interpersonal relationships increased with age and years of education. Interpersonal relationships and stress management decreased among those who reported that the pandemic had negatively affected their income. CONCLUSION: Our results indicated that COVID-19 factors are associated with Saudi adults' adoption of health-promoting behaviour.