This study aimed to determine the effects of family-integrated diabetes education on diabetes knowthe ledge of patients and family members, as well as its impact on patients' glycosylated haemoglobin (A1C). The design was a two-group Pretest Posttest quasi-experimental. The study took place at the diabetes clinics of two tertiary hospitals in southwestern Nigeria. People Living with Diabetes (PLWD) and family members aged 18 years and over and without cognitive impairment were placed, as clusters, into either a control group (CG) or an intervention group (IG) The CG comprised 88 patients and 88 family members while IG comprised 82 patients and 82 family members. Of these, 78 and 74 patients completed the study in CG and IG, respectively. PLWD in IG along with their family members were given an educational intervention on diabetes management and collaborative support with an information booklet provided. This was followed by three (3) complimentary Short Messaging Service (SMS). A1C and diabetes knowledge. Over half (52.4%) and about a fifth (18.2%) of family members and patients, respectively, had never had diabetes education. There was a statistically significant increase in the knowledge of patients and family members in IG. Unlike CG, the A1C of patients in IG improved significantly at three and six-month post-intervention, (p<0.01). Regression showed an independent effect of family members' knowledge on IG's A1C. Improved family members' diabetes knowledge positively impacted patients' glucose level. There is a need to integrate family members into diabetes care better. African Doctoral Dissertation Research Fellowship (ADDRF) award offered by the Africa Population and Health Research Center (APHRC) in partnership with the International Development Research Centre.