Despite the various innovations and treatment modalities, diabetes treatment outcomes remain sub-optimal globally and in South Africa. This places significant strain on the healthcare system. Text messaging is a cost-effective measure for promoting health. Yet, its effectiveness in improving diabetes treatment outcomes has not been documented in South Africa, especially in the resource-restrained settings. This study aims as determining the effectiveness, feasibility and acceptability of text messaging in improving diabetes outcomes in low-resource settings of the Eastern Cape Province of South Africa.This is a multi-centre, two-arm, parallel, randomised controlled trial which will compare the use of text messaging in addition to diabetes standard care to standard care alone in promoting diabetes outcomes for six months. The study will be conducted at six primary healthcare centres in two selected districts in Eastern Cape, South Africa. The study requires 216 participants if an attrition rate of 20% is anticipated. Data will be collected at baseline and six months. Randomisation will follow baseline data collection using simple randomisation, with an allocation ratio of 1:1, after removing any identifying information. The primary outcome measure is a change in mean morning random blood sugar. Secondary outcomes include change in diabetes knowledge, medication adherence, self-management, health-related quality of life, mean blood pressure, weight and clinic attendance. Data will be obtained through self-reporting using validated measures, review of clinical records and objective measurements. Data collection and measurements will follow standard procedure. Data analysis will be based on the principle of Intention-to-treat.This trial was registered in the Pan African Clinical Trial Registry, trial number: PACTR201810599931422.