Objective: To evaluate the impact of a quality improvement initiative to improve compliance of obstetric anal sphincter injuries (OASIS) management. Design: Quasi-experimental study design Setting: An academic tertiary obstetric care center. Population: Women diagnosed with OASIS from August 2018 to July 2023. Methods: An OASIS practice guideline was introduced by the urogynecology program, incorporating didactic sessions and simulation training using porcine sphincter models. The guideline emphasized primary prevention, proper diagnosis, anatomic repair technique, documentation, and post-procedure management. Compliance with guideline components—including antibiotic use, bowel regimen, short-term follow-up, and proper documentation of technique, digital rectal examination, and repair location—was compared between pre- and post-intervention cohorts. Bivariable and multivariable analyses, along with control charts, were used to assess changes. Significance level was set at p<0.05. Main Outcome Measures: Compliance with evidence-based OASIS management practices, including antibiotic use, bowel regimen, digital rectal examination, documentation, and short-term follow-up. Results: A total of 226 OASIS cases were included (168 pre-intervention, 58 post-intervention). The two groups were similar in age, race, parity, gestational age at delivery, fetal weight, and length of the second stage of labor. Post-intervention, compliance improved significantly: digital rectal examination documentation increased from 41.2% to 86.2% (RR 2.08; 95% CI 1.69–2.57; p<0.001). OASIS repair documentation increased from 7.7% to 41.4% (RR 7.57; 95% CI 4.3–13.1; p<0.001). Proper antibiotic use increased from 47.0% to 67.2% (RR 1.42; 95% CI 1.12–1.18; p=0.008). Bowel regimen utilization increased from 87.5% to 96.6% (RR 1.1; 95% CI 1.02–1.18; p=0.04). Short-term follow-up attendance increased from 35.7% to 53.4% (RR 1.49; 95% CI 1.09–2.04; p=0.01). Control charts demonstrated process changes in bowel regimen use, digital rectal examination, and OASIS documentation, but no statistical change in antibiotic use, repair in the OR, or follow-up attendance. Conclusions: Implementation of an evidence-based OASIS management guideline significantly improved compliance with key evidence-based practices, including digital rectal examination, repair documentation, antibiotic use, bowel regimen utilization, and follow-up attendance.