As the performance of late primary palatoplasty for skeletally mature patients remains controversial, there is little data available regarding speech outcomes for this patient population. The purpose of this study therefore is to identify and evaluate the impact of speech outcomes following late palate repair on skeletally mature patients. A retrospective study was performed on 19 consecutive skeletally mature patients who underwent late primary palate repair between 2010 and 2018. Speech assessment was performed preoperatively, between 3 and 6 months postoperatively, and then after 6 months postoperatively. Levels for hypernasality, oral pressure, and audible nasal air emission were scored and recorded.Patients were stratified by age, gender, presence of postoperative fistula, and Veau cleft type, in order to determine the impact of each variable on final speech outcomes. The Kruskal-Wallis test was used to compare the preoperative speech assessment with the postoperative speech outcomes, and the Mann-Whitney test was used to analyze the impact of the above variables on final speech outcomes. Our data showed overall postoperative speech improvement for all tested variables. Patients without postoperative fistula presented better results in oral pressure than those patients with postoperative fistula (P < 0.05). None of the other tested variables presented a significant negative impact on speech outcomes. Late primary palatoplasty significantly improves speech outcomes for skeletally mature patients. Fistula has a negative impact on oral pressure.