ObjectiveTo conduct a study to improve diabetes knowledge through a web‐based diabetes course in the general adult population. We hypothesised that participation in a web‐based diabetes course would have a positive impact on diabetes knowledge retention.MethodsParticipants were randomly assigned to an experimental or control group. Participants in the experimental group attended an interactive web‐based diabetes course. The Diabetes Knowledge Questionnaire (DKQ24) was used to assess the diabetes knowledge levels. The DKQ24 was completed at the beginning and end of the observation period of 3 months. The experimental group also completed it immediately after the intervention.ResultsAt the end of the observation period, a statistically significant difference in the mean rank of DKQ24 scores was found in favor of the experimental group (p < .001). The results of the experimental group had a lower interquartile range (IQR = 3) than those of the control group (IQR = 5).ConclusionsThis study suggests that providing a web‐based diabetes course to the general population is effective and can improve diabetes knowledge and retention.