Given the difficulties that people with autism spectrum disorders (ASD) have in understanding mental states and developing social skills, this research reports an educational experiment aimed at assessing whether, through a process of teaching and learning, students with ASD can improve their understanding of emotions and beliefs in a way that also involves positive changes in their daily social skills. To this end, two primary-school students and one secondary-school student with ASD participated in the design of a multiple case study. For information collection, printed teaching materials were designed and manufactured as suggested by Howlin, Baron-Cohen and Hadwin (1999), and, as a major innovation, software was designed for explicit instruction in emotions and beliefs. The students were tested on their understanding of emotions and beliefs before and after the educational procedure. We conducted a semi-structured interview with teachers and parents after the educational procedure to assess possible changes in the participating students' everyday social skills. Descriptive statistics were used to analyze quantitative data on the students' performance in handling tasks assessing their understanding of emotions and beliefs, and content analysis was used to analyze the qualitative data drawn from teachers' and parents' comments and reflections. The results suggest that, after the educational procedure, the three participating students improved their performance in tasks assessing their understanding of emotions and beliefs and that this improvement is related with their teachers' and parents' perceptions of the participants' progress in basic social skills after the experimental process.