Poor adherence to promoting health behaviours is a significant challenge for prevention and management of infectious respiratory diseases. Non-pharmaceutical Interventions (NPIs) remain a proven behavioural practice for reducing the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) currently ravaging the world. Studies on Covid-19 have primarily focused on epidemiology, virology, and potential drug treatments to the neglect of behavioural practice of low-income settings. This study examines the extent health belief model predicts the behavior of 405 urban poor residents of Ogun State, which recorded the first index case in Nigeria, towards adoption Covid-19 NPIs. A cross-sectional study was conducted to find out the relationship between study participant characteristics, HBM constructs and unhealthy behavior. Study constructs were assessed on a four point Likert scale and were mean aggregated such that higher scores indicated stronger feelings about a construct. Findings shows that urban poor in the age group 30–40 years were more likely to feel susceptible to contracting Covid-19 (mean score: 2.59 and std. dev. 0.54), they also had a higher perception of the benefit of Covid-19 preventive behaviours than participants in other age groups (mean score: 2.95 and std. dev. 0.71). Also, the most prevalent unhealthy behaviour amongst urban poor residents was the indiscriminate use of facemasks as shown by almost half (47.6%) of participants who agreed that they use facemasks all the time even when alone. The study concludes that though urban poor residents feel threatened by Covid-19, nexus of factors such as low financial earnings, inadequate knowledge, and limited access to basic medical needs hamper the effective adoption of NPIs.