ObjectiveTo determine the prevalence and associated factors of self-care behaviours among people with hypertension in the Kathmandu district of Nepal.DesignCross-sectional study.SettingMunicipalities of Kathmandu district, Nepal.ParticipantsWe enrolled 375 adults aged ≥18 years with a minimum 1-year duration of hypertension using multistage sampling.Outcome measuresWe used the Hypertension Self-care Activity Level Effects to assess self-care behaviours and collected data through face-to-face interviews. We conducted univariate and multivariable logistic regression analyses to determine the factors associated with self-care behaviours. The results were summarised as crude and adjusted ORs (AORs) with 95% CIs.ResultsThe adherence to antihypertensive medication, Dietary Approach to Stop Hypertension (DASH) diet, physical activity, weight management, alcohol moderation, and non-smoking were 61.3%, 9.3%, 59.2%, 14.1%, 90.9%, and 72.8%, respectively. Secondary or higher education (AOR: 4.42, 95% CI: 1.11 to 17.62), Brahmin and Chhetri ethnic groups (AOR: 3.30, 95% CI: 1.26 to 8.59) and good to very good perceived health (AOR: 3.96, 95% CI: 1.60 to 9.79) were positively associated with DASH diet adherence. Males (AOR: 2.05, 95% CI: 1.19 to 3.55) had higher odds of physical activity. Brahmin and Chhetri ethnic groups (AOR: 3.44, 95% CI: 1.63 to 7.26) and secondary or higher education (AOR: 4.70, 95% CI: 1.62 to 13.63) were correlates of weight management. Secondary or higher education (AOR: 2.47, 95% CI: 1.16 to 5.29), body mass index ≥25 kg/m2(AOR: 1.83, 95% CI: 1.04 to 3.22) and income above the poverty line (AOR: 2.24, 95% CI: 1.08 to 4.63) were positively associated with non-smoking. Furthermore, Brahmin and Chhetri ethnic groups (AOR: 4.51, 95% CI: 1.64 to 12.40), males (AOR: 0.17, 95% CI: 0.06 to 0.50) and primary education (AOR: 0.26, 95% CI: 0.08 to 0.85) were associated with alcohol moderation.ConclusionThe adherence to the DASH diet and weight management was particularly low. Healthcare providers and policymakers should focus on improving self-care by designing simple and affordable interventions for all patients with hypertension.