The current study sought to establish whether rate of task acquisition may be affected by the interaction between learning ability and task difficulty for children with autism spectrum disorder enrolled in an early intensive behavioural intervention (EIBI) program. To do so, specific teaching tasks selected from the Assessment of Basic Language and Learning Skills-Revised (ABLLS-R) that were previously categorized into learning ability levels were taught to two children recruited from an EIBI program. Each participant, P05 and P07, was assigned three teaching tasks that were programmed as a match, a mismatch above, and a mismatch below their current learning ability level. Teaching tasks were taught using discrete trial teaching methods for a maximum of 64 trials per task. A single teaching task, mismatched below P05’s learning ability, was mastered after 25 trials. No other teaching task was mastered within 64 trials for either participant. As this was only the first study to assess the rate of task acquisition for ABLLS-R tasks categorized into learning ability levels through direct observation, future researchers should continue to explore the effects of task difficulty on rates of task acquisition.