Background Diabetes mellitus (DM) is a growing health problem. Care programs should involve the patients to upgrade their diabetes condition and health-related quality of life (HRQoL). Objective The present study aimed to assess the effects of a psychoeducational intervention program on an indicator of glycemic control and HRQoL among type 2 diabetic patients. Methods In this quasi-experimental (pre- and postinterventional) study, 99 outpatients with type 2 diabetes were selected randomly from those attending primary health care centers in Jazan, Saudi Arabia, in 2016. Hemoglobin A1c levels (HbA1c) were measured by the colorimetric method, and HRQoL was assessed by the Arabic version of the RAND 36-Item Health Survey 1.0 (RAND-36). The psychoeducational program was conducted on the participants for 4 weeks, and preprogram findings were compared with the postprogram findings after a 5-month follow-up. Results After the intervention, there was a statistically significant reduction in the mean value of HbA1c from 9.8 to 7.7 (P < 0.001), and there was significant improvement in the mean scores of the following HRQoL scales: role limitations due to emotional problems, energy/fatigue, emotional well-being, and general health (P < 0.01). In addition, the impact of the program on HRQoL was better among males and among patients who were older than forty years than among women and patients who were forty years old or younger. Conclusion The application of such psychoeducational intervention programs can be helpful in the improvement of HbA1c levels and HRQoL for patients with DM.