Large scale testing in English affects second-language students not only greatly but also differently than first-language learners. The research literature reports that confounding factors in such large-scale testing such as varying test formats may differentially affect the performance of students from diverse backgrounds. An investigation of test performance between ESL/ELD students and non-ESL/ELD students on the Ontario Secondary School Literacy Test (OSSLT) was performed to investigate whether test formats in reading comprehension affected the two groups differently. The results indicate that the overall pattern of difficulty levels on the three test formats were the same between ESL/ELD students and non-ESL/ELD students, except that ESL/ELD students performed substantially lower on each format and that more variability was found among ESL/ELD students. Further, discriminant analysis results indicated that only the multiple-choice questions obtained a significant discriminant coefficient in differentiating the two groups. The results suggest a lack of association between test formats and test performance.