Introduction: Food security, defined as consistent access to sufficient, safe, and nutritious food, remains a significant challenge in Malaysia, especially among lowincome households. This study examined associations between food expenditure, food consumption, food adequacy, and food security among lower-ranking prison officers in the B40 income group. Methods: Multistage sampling was used to select study locations and prisons in Malaysia. Purposive sampling was used to select 420 officers, who completed a self-administered, validated questionnaire. Data were analysed descriptively and through multiple linear regression to identify key predictors of food security. Results: All respondents (100%) had acceptable Food Consumption Scores (FCS), with 97.1% showing high food adequacy. However, the vast majority (89.5%) were classified as at risk of food insecurity. Food spending was predominantly directed towards staple cereals and animal proteins, such as chicken and meat, while expenditure on fruits, vegetables, and dairy products was much lower. Food expenditure was strongly linked to food insecurity (β =-0.588, p<0.001). Similarly, food consumption score (β =-0.087, p=0.038) and food adequacy (β =-0.127, p=0.003) were both negatively associated with food insecurity. Conclusion: Although Malaysian prison officers generally had adequate diets, a substantial proportion of households remained food insecure, particularly in terms of dietary diversity and micronutrient intake. Household food expenditure, consumption scores, and food adequacy were all linked to lower food insecurity.