There is limited research demonstrating direct instruction (DI) as an effective language intervention for students with autism spectrum disorders (ASD) and developmental disabilities (DD). Existing research has shown that instruction using partial implementation of DI programs resulted in student learning (Ganz, 2007) and instruction using whole lessons resulted in positive instructional effects for students with ASD and DD (Ganz, 2007). However, it is not known whether DI is more effective than other language interventions. The purpose of this study was to compare DI to an established intervention, discrete trial teaching. Thirteen students with ASD or participated in the study and data were collected using curriculum-based assessment. An independent samples t-test indicated that there was a statistically significant difference in student performance for the group who received DI. Results and their implications will be discussed.