The main objective of the present study has been to verify the effectiveness of an intervention program on the lexical organization of pupils with Typical Development and with developmental language disorder. A total of 99 five-year-old pupils from schools in the Tenerife Island (Canary Islands, Spain) participated. The subtests of expressive vocabulary and of receptive and expressive word classes of the CELF-4 were used. The intervention program consisted of 75 sessions lasting 20 minutes each. The results indicated that pupils diagnosed with developmental language disorder initially performed worse in vocabulary and word classes than those with TD. Also, the pupils with developmental language disorder not only improved their performance by the end of the program, but were found to be the group with the greatest gains from the intervention. There are educational implications for organizing an early intervention of an inclusive nature.