This study was a quasi-experimental design (QED) that examined the impact of Intervene K-12 tutoring on mathematics achievement for Grade 9 ELL students identified by HPS as having experienced considerable learning disruptions as a result of the COVID-19 pandemic and having recently arrived in the United States. Achievement gains for treatment students, who received tutoring services, were compared to those of comparison students, who did not receive tutoring. Comparison students were selected by using propensity-score matching (PSM) techniques in order to identify students who were most similar to treatment students. The main outcome variables of interest were end-of-course (EOC) and Final Algebra I exam scores, as well as spring 2023 PSAT mathematics scores, while beginning-of-course (BOC) Algebra I exam scores and spring 2022 PSAT mathematics scores were used as prior mathematics achievement variables. Multiple regression analyses were used to examine the impact of Intervene K-12 tutoring on mathematics achievement gains. The results of the impact analyses showed generally positive mathematics achievement trends for Intervene K-12 tutoring students. Treatment students outgained matched comparison students on the EOY Algebra I exam by more than 7 points. Similarly, treatment students outgained comparison students on the spring PSAT math assessment by 5 points although these impacts did not reach statistical significance. The effect size of the EOC Algebra I score impact was nearly 0.40 SDs, indicating a medium-to-large practical impact of tutoring on student mathematics achievement.