Background: Parental involvement in early childhood is foundational to a child's later academic achievement (Heckman, 2007). Parent-child book reading is frequently recommended as a way to build a child's early cognitive skills. Evidence suggests that mother-child reading time increases children's vocabulary and reading skills (Price & Kalil, 2019), and interventions that promote family literacy activities in kindergarten have been successful at increasing children's achievement in elementary school (Senechal & Young, 2008). Despite the evidence, some parents do not engage in shared book reading, possibly due to a lack of time, resources, or information on the importance of shared reading (York et al., 2019). These barriers are likely intensified for low-income families who may face added time and resource constraints, and report spending less time engaging in educational activities with their children than high-income parents (Bradley & Corwyn, 2002). Additionally, children in these families may also have the most to gain from home reading activities. Purpose: We address two research questions: 1. Did Zoology One curriculum increase the classroom level of home reading in treated kindergarten classrooms when compared with a business as usual literacy curriculum? 2. Were treated student literacy outcomes affected by their exposure to high classroom levels of home reading? Setting: This study took place in kindergarten classrooms in the School District of Philadelphia, a large urban school district. The program was implemented with two cohorts of kindergarteners in the 2016-17 and 2017-18 school years. Participants: Over 1500 kindergarten students in 71 classrooms were included in the study. Approximately 70% of the students were from low-income households, as determined by the district's meal accounting, and 15% are from homes with a primary language other than English. Intervention: The Zoology One curriculum (now called ARC Core) combines early literacy curricular components, such as high exposure to text, independent reading, small group instruction, and teacher coaching, with high interest science concepts. The curriculum is designed to build a culture of literacy and to capitalize on student's natural interest in animals and science to encourage students to engage more deeply in literacy development. In this paper, we focus on the home reading component of the kindergarten literacy curriculum. Teachers were coached to assign home reading and to encourage families to complete 30 minutes of reading with their kindergartener nightly. The books were tailored to each student's reading level and progressed as their skills developed over the year. Three key mechanisms related to the home reading component that drive the theory of change are that reading at home increases the volume of reading done in class, take home books were tailored to specific student learning goals, and the books align with classroom instruction creating a cohesive experience for young learners as they develop literacy skills. Research Design: In the original multi-site cluster-randomized study, kindergarten classrooms were randomized to receive Zoology One or business-as-usual condition instruction. For this follow up analysis, we are interested in the effect of higher levels of home reading on student outcomes. Data Collection & Analysis: Our data include longitudinal data on literacy development from 1,517 students in 68 kindergarten classrooms, teacher surveys, and reading log data. First, we examine the effect of the curriculum on teacher assignment of home reading. Our identification relies on balanced random assignment (balance tests confirm) from the RCT to estimate effects of the curriculum on teacher reported levels of home reading. Second, we explore the role of exposure to high classroom levels of home reading assigned through the curriculum on children's literacy development. Home reading was not randomly assigned so we use multiple strategies to estimate upper and lower bounds of the effects of being in a high home reading classroom. We use a principal stratification method, similar to that used to estimate a complier average causal effect (Miratrix et al., 2018; Page et al., 2015). Findings: The RCT found that the curriculum improved passage comprehension (0.16 SD), letter naming fluency (0.28 SD), and motivation to read (0.32 SD) (Author et al., forthcoming). Gains were larger among classrooms with high fidelity, which was driven by variation in assigned home reading. Thus, the motivation for this paper in addressing the role of assigned home reading in literacy development and mitigating gaps. Results demonstrate that home reading was increased by the curriculum with the average treated student completing nearly 40 minutes more of home reading in a typical week compared with students in the business as usual condition. Further, our preliminary bounded estimates of the effects of home reading show students in treated classrooms with higher levels of home reading appear to experience greater effects from the program than those who were in treated classrooms with lower levels of home reading. Conclusions: Together, our results demonstrate the potential efficiency gained through engaging parents/caregivers in bridging literacy instruction from the classroom to a child's home. This work seeks to contribute to our understanding of the importance of a home reading component embedded into a larger classroom level literacy curriculum.