OBJECTIVES: This multicountry analysis aimed to assess the prevalence of key hygiene prevention behaviours and their determinants, associated with international non-governmental organisation (WaterAid) hygiene behaviour change programmes for COVID-19 prevention. The goal of this analysis is to inform future outbreak preparedness and pandemic response in low and middle-income countries. DESIGN: Cross-sectional study. SETTING: Households in seven countries where WaterAid implemented a first-phase COVID-19 response programme in 2020 (Ethiopia, Ghana, Nepal, Nigeria, Rwanda, Tanzania and Zambia). PARTICIPANTS: 3033 adults (1469 men and 1564 women, alternately sampled from one household to the next to maintain gender balance) in specific programme areas (211 villages) surveyed between October and November 2020. PRIMARY OUTCOME MEASURES: Self-reported primary outcomes were: a composite measure of HWWS for prevention of respiratory infection/COVID-19 (total of 5 key moments); respondent increased HWWS behaviour after the COVID-19 pandemic; respondent always wears a mask in public spaces; respondent always practices physical distancing in public spaces. RESULTS: Most respondents (80%) reported increasing their handwashing behaviour after the pandemic, but practice of HWWS at COVID-19-specific prevention moments was low. Mask wearing (58%) and physical distancing (29%) varied substantially between countries. Determinants of key behaviours were identified, including age and socioeconomic status, perceived norms, self-regulation and the motive of protecting others. Incidence rate ratios or odds ratios and 95% CIs for a range of psychosocial determinants for each of the four primary outcomes are reported. CONCLUSIONS: These findings highlight that leveraging behaviour-specific emotional drivers and norms, reducing common barriers and promoting targeted messages about specific behaviours and actions individuals can take to reduce risk are necessary to support large-scale behaviour change. Learning from the COVID-19 response to more effectively integrate novel behaviours into existing health promotion will be vital for disease prevention and outbreak resilience.