The purpose of this research is to examine the English language proficiency trajectories of 2,201 fourth- through eighth-grade Latino English learner (EL) students who differed by current English language proficiency and were enrolled in a dual language program. Results showed that (1) students in the four English language proficiency groups varied significantly in all outcome measures in English and Spanish (Fluent English Proficient > Advanced > Intermediate > Beginner) by upper, but not K/1 entry, grades and (2) examining students' trajectories shows the importance of bilingual, not just English, proficiency at school entry.