Educational achievement gaps change by season. While students from different class backgrounds learn at similar rates when school is in session, over the summer class-based achievement gaps grow the fastest. The story is different for race-based achievement gaps. Black/white achievement gaps tend to widen more during the school year than over the summer. However, researchers have largely overlooked English learners (ELs), who are likely to be highly sensitive to summer break, a time when they are away from school and may not have enough exposure to an English language environment. In addition, summer learning scholars have long demonstrated that family socioeconomic status is the main driver of summer learning, but they fail to account for potential neighborhood effects on summer learning. Using administrative and assessment data from the Houston Independent School District (HISD), this dissertation addresses these gaps with three empirical studies. The first compares learning trajectories of three groups—Els whose home language is other than English, English proficient students whose home language is other than English, and English proficient students who speak English at home. I found reading learning gaps between English proficient students whose home language is other than English and the other two groups widen further during the academic year, but not during the summer. The second study assesses neighborhood effects on students’ reading learning rates, using 3-level piecewise linear models with neighborhood characteristics incorporated. Results indicate that concentrated disadvantage and violent crime have stronger effects on students’ reading outcomes during the academic year than in the summer. The third empirical piece examines the causal effects of a remedial summer program with two regression discontinuity designs. Results demonstrate that students who were at the margin of summer school eligibility did not benefit significantly from summer school. Taken together, these findings suggest that educational achievement gaps increase faster during the academic year than during the summer break.