The current research aimed to assess and train relational framing of categorization in young typically developing children and to assess the impact of training on relevant measures of language and categorization. In two experiments, children were assessed and trained in mutual and combinatorial entailment and transformation of function. In Experiment 1, five year olds were assessed and trained in arbitrary containment while in Experiment 2 six year olds were assessed and trained in arbitrary hierarchy. Both experiments employed a multiple baseline design across responses and participants and compared children receiving training with controls. In both experiments, correct responding increased to criterion levels on introduction of training, and both generalization and maintenance was observed. In both cases, the training group showed better performance than controls on related measures. Results are discussed in relation to previous research and for implications with regard to future studies on relational framing and categorization in children.