The population of English Language Learners (ELLs) in the United States, in the K-12 context, is diverse and comprised of lesser-known subordinate groups including Long-term English Language Learners (LTELLs). The LTELL designation refers to students who, after attending schools for six or more years, still require English as a New Language (ENL) support services (Olsen, 2010b). These students are known to have stalled academic proficiency, and remain in protracted ELL status, unable to master the content necessary to pass the state mandated benchmark English language proficiency tests. There is a small but growing body of literature that addresses LTELL students' academic and social characteristics (e.g. Menken & Kleyn, 2010; Olsen, 2010b). The current review seeks to add to the extant body of knowledge on LTELLs by classifying, synthesizing and evaluating previous scholarship on this population. This review is undergirded by the following research questions: (RQ1) What are the proficiency factors of LTELLs? To what extent do these proficiency factors affect language and literacy development? (RQ2) What are the instructional factors and intervention practices which affect LTELLs? To what extent do these instructional factors impact LTELLs literacy and language development? (RQ3) What are the affective factors which affect performance for LTELLs? To what extent do these affective factors impact LTELLs literacy and language development?