Food labels are a widely available tool for making informed dietary decisions, yet their use in people managing type 2 diabetes mellitus (T2DM) or pre-diabetes remains poorly understood, particularly in the Australian context. Grounded in Social Cognitive Theory (1), which positions behaviour as shaped by the interaction between personal knowledge, attitudes, and environmental factors, this study aimed to investigate food label knowledge, attitudes, and use among Australian adults with T2DM or pre-diabetes, identify barriers to use, and determine independent predictors of food label use. A cross-sectional online survey was conducted between June and December 2025 using the Qualtrics platform and an instrument adapted from Rose et al. (2), which assessed food label knowledge (22 items), use (20 items), attitudes (7 items), and seven barrier domains, each rated on a five-point Likert scale (1 = Strongly Disagree to 5 = Strongly Agree). Participants were recruited through Facebook advertising and two online research panels (Researchify and JoinUs). Eligibility criteria included being aged 18 years or older, residing in Australia, having a self-reported diagnosis of T2DM or pre-diabetes, and being involved in their own grocery shopping. A total of 245 participants met the inclusion criteria and completed at least 80% of survey items. Descriptive statistics, Pearson correlations, independent samples t-tests, and one-way ANOVA were used to examine associations between participant characteristics and food label use. Hierarchical multiple linear regression was conducted to identify independent predictors. The mean food label knowledge score was 59% correct. 24.8% of participants were classified as high food label users, and 36.7% held a positive attitude towards food labels (mean scores ≥4 out of 5). Among the food label components assessed, sugar (77.6%) and total carbohydrate (60.8%) were the most frequently consulted, while nutrition and health claims (29.9%) and the Health Star Rating (40.1%) were the least used. Small font size was the most endorsed barrier (60.4%), followed by time limitation (51.3%) to use food labels. In the final regression model (adjusted R² = 0.47), attitude was the strongest predictor of food label use (β = 0.430, p < 0.001). Food label knowledge was significant in earlier models but lost significance once barriers were introduced (β = 0.100, p = 0.080). Vegetable intake (β = 0.130, p = 0.029) and grain intake (β = 0.130, p = 0.026) were significant positive predictors. Viewing food labels as not a priority was the only barrier negatively associated with use (β = -0.230, p = 0.003). These findings suggest that interventions targeting attitudes towards food labels and their important role in diabetes self-management, alongside policy attention to label readability, are likely to be more effective than knowledge-based education alone in supporting informed food purchasing among Australians with T2DM or pre-diabetes.