Diabetes presents significant self-care challenges that require sustained motivation. Motivational Interviewing (MI) has substantial support in enhancing motivation for behavioral change, but its effective application in routine healthcare requires practitioners to acquire and use related skills. The aim of this systematic review was to investigate the impact of MI training on MI-related skills of practitioners who provide diabetes healthcare. PubMed, EMBASE and PsycINFO were searched using the terms motivational interviewing, motivation enhancement, and diabetes. Two assessors independently screened titles, abstracts and full texts for papers reporting the impact of MI training on diabetes healthcare practitioners' outcomes. Of 625 abstracts screened, 22 papers from 17 unique studies were included. All 17 studies reported some improvement in MI skills, with 14 finding improvements in more than 50% and three less than 35%. However, risk of bias and outcome measures varied widely between studies. All studies showed diabetes healthcare practitioners acquired and applied MI skills post-training, to varying levels. Findings suggest training should include education, role play, and ongoing supervision to maintain skills.