Research on newcomers' language and literacy (L&L) skills has expanded recently in response to the growth of this population. To inform teachers and researchers, this paper reviewed 41 empirical studies (2010-2022) on high-school newcomers' L&L. Most studies used qualitative methods, working with few participants for short time periods. Four themes emerged. First, studies highlighted affordances of leveraging students' home languages but also identified cases when home language use hindered students' learning. Second, researchers described language scaffolding practices that promoted content-area learning. Third, studies examined the potential of L&L to connect to newcomers' identities and develop a sense of belonging in the classroom, though some studies documented cases of marginalization and isolation. Fourth, researchers found peers offered language support, but successful peer interactions hinged on certain conditions. Altogether, this review offers preliminary implications for practice and calls for research that investigates with increased nuance the potential of specific L&L practices.