We investigated whether participants with higher adherence to smartphone or paper-based self-monitoring of diet, physical activity, blood glucose, and body weight have a beneficial impact on their body weight and hemoglobin A1c measures over a 3-month period. Data were combined from two intervention studies that recruited overweight or obese participants with type 2 diabetes. Three clusters of adherence to self-monitoring were identified. Participants in a cluster with high adherence to self-monitoring of diet and moderate adherence to glucose self-monitoring were found to have the biggest reductions in weight and hemoglobin A1c, as compared to clusters with either high or low adherence to self-monitoring of all four factors.