<p>​Food insecurity remains a significant challenge in Bangladesh’s urban slums, which are still considered neglected communities. This study aimed to explore the factors associated with food insecurity and dietary diversity status among slum households of Khulna Division, Bangladesh. This study employed a cross-sectional design, incorporating a household survey and key informant face-to-face interviews. A multi-stage sampling technique was used to select Bangladeshi slum dwellers (<i>n</i> = 749) ≥ 18 years old from five districts residing in the Khulna Division. Data were collected using a pretested structured questionnaire. The household vulnerability to food insecurity indicator and dietary diversity status were used to assess the level of vulnerability to food insecurity. A logit model was used to identify the determinants of vulnerability to food insecurity in slum households. In this study, about 74.6% of the households were mild-to-moderate (MMFI) food insecure while 22.1% experienced severe food insecurity (SFI). Similarly, above 42% of the household respondents had low household dietary diversity (HDDS) and moderate HDDS. We revealed that monthly income, occupation, household size, anxiety and uncertainty, inadequate quality, and insufficient food intake were significantly associated with household dietary diversity and food insecurity status. Additionally, household respondents with MMFI and SFI status have significantly more experience with potential risk indicators of low and moderate HDDS. The study highlighted that in slum areas, households have higher levels of food insecurity and low household dietary diversity status, which may create a negative impact on their mental health and well-being. Therefore, the ongoing and future governments should prioritize supporting vulnerable communities to ensure food security by providing food packages and reducing food prices.</p>