Peer relationships form the bedrock for numerous developmental outcomes, including students’ social-emotional wellness, their sense of belonging, their decision-making, and the development of their sense of self. While educators acknowledge the importance of students’ social-emotional well-being and their relationship building, these concepts are often thought of as secondary to developing students’ academic achievement, particularly considering the oversized role of high-stakes testing in the US educational system. However, the divide between social interactions and academic achievement is not as stark as policymakers may make it seem. Indeed, research by developmental psychologists and education researchers has long documented that having strong peer relationships will allow children to thrive, including on academic development. This three-paper dissertation aims to provide evidence demonstrating the relation between being connected to one’s peers, reading achievement, and the development of executive functioning skills for elementary-aged students, including on a sample of primarily English Learners. Throughout all three studies, data were collected as part of Project LEARN, a three-year longitudinal study that measured various components of reading development alongside executive functioning and other variables, ultimately aiming to compare reading trajectories for elementary-aged English Learners and English Monolinguals. Paper 1, “Peer Effects on Oral Language Comprehension in Elementary School: A Social Network Analysis” uses student friendship nominations across three semesters (N=414) as well as students’ oral comprehension scores. This paper asks, What is the relation between student centrality (i.e., being connected to one’s classroom peers) and change in academic achievement, as measured by oral language skills? After generating social networks using the friendship nominations, I calculated how central each student was within their classroom friendship network. Using a student fixed effects model comparing students’ oral comprehension growth as a function of their classroom centrality, I find that students’ predicted oral comprehension growth is significantly greater when students are more central within their classroom network, even after controlling for other reading variables in the model. This paper supports the connection between peer relationships and academics (using oral language as a proxy), suggesting that reading interventions and pedagogy should leverage peer relationships as one way to improve student learning. Paper 2, “The Differential Relation between Friendship Centrality and Reading Outcomes for English Learners,” uses the same data as Paper 1, focusing on whether student centrality differentially predicts reading outcomes for English Learners and English Monolinguals. This paper asks, a) To what extent does classroom friendship centrality predict reading achievement gains for English Learners? and b) To what extent does the relationship between classroom friendship centrality and reading achievement gains differ between English Learners and English Monolinguals? I used a series of multiple linear regression models, with students nested in homeroom classrooms, to answer the two research questions. First, using a sample of only English Learners (N=160), I find that English Learners are more likely to experience significant gains in oral language comprehension—but not reading comprehension—when they are more central within their classroom network. Using the full sample of students (N=229), I find that English Monolinguals are significantly more likely to experience gains in reading comprehension when they are more central within their classroom friendship network, but there is no relation between friendship centrality and reading comprehension development for English Learners. This surprising finding, that friendship centrality predicts English Learners’ oral language development but not their reading comprehension development, raises pedagogical questions about how best to support English Learners’ reading outcomes. More research is needed, with particular attention focused on whether English Learners who are more connected within their classrooms experience similar levels of self-efficacy and sense of belonging as their connected English Monolingual peers. Paper 3, “Do Executive Functioning Skills Predict Reading Comprehension Growth?” uses students’ executive functioning composites—consisting of inhibitory control, cognitive flexibility, and memory scores—and reading comprehension scores in two subsequent semesters. This paper asks, To what extent do students’ growth in executive functioning predict their reading comprehension growth? Using two methods that aim to limit omitted variable bias—multiple regression with covariate adjustment and propensity score matching—I find that students’ growth in executive functioning significantly predicts their reading comprehension growth. This study provides support that interventions targeting students’ executive functioning may also contribute to their reading development.