Previous research examining the reading achievement of children speaking languages other than English at home has often grouped such children into one broad category at kindergarten entry--English learners (ELs). EL categorization and placement, however, can considerably underestimate the heterogeneity present among language minority children in terms of their language proficiency and needed English skills. The purpose of our study is twofold: (i) to compare the early elementary (K-3) reading growth patterns among four language background groups of children according to parents' reported home language use and (ii) to examine the association between student family demographics and home learning environments and students' growth trajectories. We utilized a "known group" analytic approach--multiple-group latent growth analysis, and an "unknown-group" approach--growth mixture analysis to investigate the heterogeneity in multilingual students' reading growth trajectories. The known groups consisted of four language backgrounds based primarily on parents' self-reported home language. Results indicated a sizable gap between LEP children and the other language background groups, albeit with the LEP group demonstrating significant greater growth during first grade than the others. The unknown-group approach identified four emergent reading profiles with different kindergarten entry skills and growth rates. We found English bilingual students were overrepresented in the medium-high and high achieving groups. Further, family socioeconomic status and home literacy practices were robust predictors of children's reading achievement progress throughout the study, a finding diverging from the known-group approach. We discuss ways the study extends previous research examining language minority students.