Background: While a significant body of research has addressed teachers' evaluations of mainstream English speaking students, there is a dearth of such research focusing on immigrant adolescents. As many immigrant students are in the process of acquiring English language proficiency, evaluating and assigning grades to immigrant youth can pose particular challenges. Grades assigned for oral or written products may underestimate English language learners' knowledge, content skills or achievement. Conversely, relying excessively on effort or class behaviour rather than actual academic performance may inflate immigrant students' grades. Purpose: We examined the extent to which immigrant students' academic achievement indicated by grades is attributable to factors such as English language proficiency, course understanding, classroom behaviours and homework completion. We then examined whether the effect of homework completion on grades varied as a function of English proficiency. In addition, we examined the factors contributing to teachers' evaluation of immigrant students' level of course understanding. Lastly, we investigated whether the effect of homework completion on course understanding varied as a function of English proficiency. Sample: This study examined the final year (2002) data of the five-year Longitudinal Immigrant Student Adaptation (LISA) study. At the start of the original study, the participants were recently arrived immigrant youth (ages 9-14) from Central America (El Salvador, Guatemala, Honduras and Nicaragua), China, the Dominican Republic, Haiti and Mexico; they were recruited from seven public school districts in the USA in Massachusetts and California. The present study was a secondary analysis of a subset of final year LISA data, involving data from 273 students and 57 teachers. Methods: Using data collected through structured student interviews and behaviour checklists completed by teachers, we conducted hierarchical regression analyses to identify the factors that contributed significantly to immigrant students' grades and to their course understanding. Further regression analyses were conducted to determine whether English language proficiency was a moderating variable on immigrant students' grades and their level of understanding in a course. Results: There were four main findings. Firstly, the regression results indicated that homework completion and English language proficiency had significant impact on class grades. Secondly, the effect of homework completion on grades was not moderated by students' English proficiency. Thirdly, immigrant students' class behaviours, English proficiency and homework completion largely determined teacher evaluations of students' course understanding. Fourthly, the effect of homework completion on teacher evaluations of students' course understanding was moderated by English proficiency. For students with high English language proficiency, completing homework significantly affected teacher assessments of their course understanding. For students with low English language proficiency, however, completing homework had relatively little effect on teacher assessments of their course understanding. Conclusions: In this exploratory study, grades assigned to immigrant students were largely determined by whether they do their homework and their English language proficiency. Teacher evaluations of immigrant students' level of course understanding were largely determined by students' class behaviours, English language proficiency and homework completion. It is suggested that teachers distinguish between effort and skill and provide separate feedback for each of these dimensions during the process that newcomer immigrant students are concurrently acquiring academic skills while mastering a new language. However, further investigation is needed to determine the generalisability of findings to a larger immigrant youth population. (Contains 6 figures, 8 tables and 1 note.)