AimsTo assess trajectories in cardiometabolic markers among people with type 1 and type 2 diabetes with varying health literacy levels. MethodsSurvey data assessing self-reported health literacy among 1401 people with type 1 diabetes and 910 people with type 2 diabetes were linked to prospective clinical data. Mixed effects modelling was used to identify the impact of three health literacy domains on trajectories of systolic blood pressure (SBP), low-density lipoprotein cholesterol (LDL-C), and glycated hemoglobin (HbA1c). ResultsHigh health literacy scores in some domains were associated with attenuated HbA1c trajectories, while associations with LDL-C and SBP were weak or absent, particularly among participants with type 2 diabetes. The domain “Ability to Actively Manage Health” had the strongest association with HbA1c (P < 0.001). Exponential changes over time were not observed. Differences in the estimated progression of cardiometabolic markers by health literacy levels did not reach statistical significance. ConclusionLow health literacy was associated with suboptimal glycaemic levels in type 1 and type 2 diabetes. There was inconclusive evidence of associations between health literacy, BP, and LDL-C. Development in cardiometabolic markers did not indicate faster diabetes progression among people with low health literacy.