Teachers’ professional development is the key to education improvement. On that basis, the present study aimed to investigate the impact of a 6-month in-service training program in the context of the continuing professional development for educators on educational practice. The main objective of the training program was to improve the educators’ teaching skills, to enrich their practices with the most effective strategies and with the newest findings from research evidence in order to increase the quality of their educational interventions for students with special educational needs. An innovation of that program was the simultaneous training of both general and special education teachers in pairs, smoothing the dividing lines between general and special education in their daily instructional practice. The participants were 30 educators, divided into 15 pairs. Each pair was working in the same inclusive school sharing the responsibility of the educational support of a student with learning problems. The estimation of the impact of the program was investigated by measuring the educators’ increasing sense of self-efficacy in relation to their instructional skills and overall effectiveness of their educational interventions for their students with learning difficulties. A pre and post evaluation research design was employed and the findings showed that the training program had a positive impact on the educators’ self-efficacy and their effectiveness regarding collaborative educational interventions for their students.