In this study, the researchers aimed to compare the effectiveness and efficiency of simultaneous prompting procedure in which non-target information was in the antecedent and consequence of teaching trials while teaching core academic skills from general education curriculum to three students with autism spectrum disorder (ASD) in high school mainstreaming classroom who were aged 16 to 17. For this purpose, the researchers used an adapted alternating treatments design. Additionally, the researchers collected social validity data from students with ASD through subjective evaluation and analyzed them descriptively. The effectiveness findings showed that all students acquired target academic skills and non-target information provided in both teaching procedures. Efficiency findings showed that the procedure in which non-target information in the antecedent was more efficient for all parameters except the number of minutes of instruction to criterion. In fact, the procedure in which non-target information in the consequence was shorter in length for one student. Finally, social validity findings showed that all students indicated positive opinions regarding target skills, intervention process, and the outcomes. Limitations and implications for practice and future research are discussed.