The study presents the results of a comparative study in which videos and a 3D virtual environment were used for teaching school-related functional skills to students with ADHD or developmental dyslexia, displaying challenging behaviors. The participating students (sixteen 8 to 9 years old) were divided into two groups. To the first, videos were used and the second used the virtual environment. To both, a school environment was presented, students observed how they were expected to behave, and had to demonstrate what they have learned. Each student attended a total of three two-hour sessions. Data were collected by means of observations. The results indicated that students in the second group significantly improved their functional skills in terms of the number of behaviors that were retained and manifested in the real school environment. Thus, it can be argued that virtual environments are a promising tool for teaching functional skills to students with ADHD or developmental dyslexia, displaying challenging behaviors. Implications for research and practice are also discussed.