This study explored outcomes related to students' participation in a Houston Symphony (HS) partnership at a targeted HISD elementary school. Students received weekly in-school core enrichment instruction and after-school violin instruction by Houston Symphony Community-Embedded Musicians throughout the 2018-2019 academic year. The study found that students in the HS Core Enrichment/After-school Violin group had the highest combined English and Spanish STAAR mean reading scale scores among third- and fifth-grade students in 2019, while the HS After-school Violin Only students had the highest mean scale score among fourth-grade students. In mathematics, the HS Core Enrichment/After-school Violin group achieved the highest mean scale score at the third and fifth-grade levels; whereas, the After-School Violin Only group attained the highest mean scale score at the fourth-grade level on the combined tests in 2019. Paired t-test analyses showed statistically significant improvements in the mean STAAR mathematics scale scores of the HS Core Enrichment and HS Core Enrichment/After-school groups as well as the Non-HS control group as students progressed from third to fourth and from fourth to fifth grades (2018 to 2019). Difference-in-differences (DiD) analyses revealed more consistent benefits in Houston Symphony-group participation over the control group of students who did not participate in the Houston Symphony. The highest increases in attendance rates over the past two years as students progressed from third to fourth and from fourth to fifth grades were among the HS Core Enrichment/Afterschool Violin group. Retention of the fifth-grade student cohort in orchestra at middle schools was eight percent, which is estimated to be below the national average. Expansion of the Houston Symphony partnership to middle and high schools may help to improve retention outcomes for students in orchestra at these levels.