This study explored the effects of an evidence-based literacy program, ABRACADABRA, on the spelling abilities of children with autism spectrum disorder (ASD). Twenty children with ASD aged 5–11 years were assigned to matched instruction and waitlist control groups. Children in the instruction group received 26 hrs of individualized, home-based instruction using ABRACADABRA over a 13-week period. Results showed no change in children’s conventional spelling accuracy skills following ABRACADABRA instruction. However, an analysis of spelling attempts using the Computerized Spelling Sensitivity System (Masterson & Hrbec, 2011) revealed statistically significant gains in linguistic spelling accuracy for children in the instruction group relative to the waitlist control group, with large effect sizes. These findings suggest that ABRACADABRA improves aspects of spelling ability in children with ASD and that the Computerized Spelling Sensitivity System is a useful tool for detecting changes in the spelling abilities of children with ASD following literacy instruction.