Students with emotional and/or behavioral disabilities (E/BD), including students with emotional disturbance and attention deficit hyperactivity disorder, receiving special education services perform significantly worse on academic performance measures than same age peers. Researchers have focused on reading and math performance while less is known about the writing performance of students with E/BD. We examined the writing performance of students with E/BD and compared their writing performance with that of students without disabilities. In addition, we examined the mediating effect of reading performance on differential writing performance for students with E/BD and typical peers. A sample of 114 students with E/BD was compared with both a full sample of 3,187 typical students and 114 students matched with the E/BD students using propensity score matching. Students were compared on their writing and reading performance on the Connecticut State Mastery Test. Results indicate that students with E/BD perform significantly worse than propensity score-matched peers in writing. Mediation analyses indicate that reading performance accounts for ~60% of the total variance of writing performance for students with E/BD. Implications and future directions for researchers are discussed.