The Relational Completion Procedure is effective for establishing same, opposite and comparative derived relations in verbally able adults, but to date it has not been used to establish relational frames in young children or those with developmental delay. In Experiment 1, the Relational Completion Procedure was used with the goal of establishing two 3‐member sameness networks in nine individuals with Autism Spectrum Disorder (eight with language delay). A multiple exemplar intervention was employed to facilitate derived relational responding when required. Seven of nine participants in Experiment 1 passed tests for derived relations. In Experiment 2, eight participants (all of whom, except one, had a verbal repertoire) were given training with the aim of establishing two 4‐member sameness networks. Three of these participants were typically developing young children aged between 5 and 6 years old, all of whom demonstrated derived relations, as did four of the five participants with developmental delay. These data demonstrate that it is possible to reliably establish derived relations in young children and those with developmental delay using an automated procedure.