This study investigated the roles of public health on disease prevention through behaviour modification in North-West Nigeria. To achieve this, six research questions, one major hypothesis and five sub-hypotheses were formulated. Descriptive survey research design was adopted in carrying out the study. The population of this research comprised residents of selected states in North-West Nigeria, from which respondents were drawn using multi-stage sampling procedures. A researcher-designed questionnaire titled Public Health and Behaviour Modification Questionnaire (PHBMQ) with a reliability coefficient of 0.80 was used for data collection. In addition, interviews with health officials and community leaders were conducted to strengthen the findings. Out of the copies of the questionnaire administered, only those duly completed and returned were used for data analysis. Frequency count and percentage were used to organize and describe the demographic data of the subjects, while Chi-square and ANOVA were employed to test the hypotheses at 0.05 level of significance. The results of the study revealed that public health interventions such as health education, sanitation campaigns, vaccination, and awareness programmes significantly influence disease prevention through positive behaviour change among communities in North-West Nigeria. Findings further indicated that cultural practices, poverty, inadequate facilities, and attitudes of health personnel are major factors affecting sustained behavioural modification.