Language development involves the learning of multiple sets of equivalence relations. Research has shown that if certain conditional relations are directly taught for one member of a class of stimuli, then additional conditional relations often emerge for other members of that class, without direct training. There are currently very few studies which have demonstrated this research finding in individuals with autism spectrum disorder (ASD). The research design used for the present experiment was a single-subject AB cross-over design replicated across five plus five children with ASD and five plus five typically developing children. The children with ASD and the typically developing children were matched on their level of vocabulary development. Participants were randomly assigned to either a teaching order Treatment A+B or a teaching order Treatment B+A. The first experimental treatment (Treatment A+B) involved teaching responses to S1 and S2 in the order Condition A followed by Condition B. The second experimental treatment (Treatment B+A) involved teaching responses to S1 and S2 in the order Condition B followed by Condition A. Condition A involved the teaching of AB and AC (hear-select) relations, and Condition B involved the teaching of BA and CA (see-say) relations. The participants in this study were taught stimulus-response relations that involved six names and numerical representations of quantities in the range 1 to 18. Tests for the emergence of symmetry and transitivity were then conducted. The relationships between the emergence of the untaught equivalence relations and teaching condition, the entering characteristics of the children, and trials to criterion were examined. The results of this study showed that five out of ten participants with ASD demonstrated the emergence of all of the untaught equivalence relations regardless of the treatment condition. The remaining five participants with ASD showed substantial variability. Of the children in the Typically Developing Group nine of the ten demonstrated emergence of all of the untaught equivalence relations. The variables that were most strongly correlated with the emergence of untaught equivalence relations were speed of acquisition of taught relations, functional academics scores, and the chronological age of the participants. The effect of communication ability, pre-academic numeracy skill level, and the experimental treatment (the teaching order conditions) were not strongly related to the emergence of untaught equivalence relations. These findings suggest that outcomes on tests for emergence may have been a function of children’s rate of development and prior learning history. The findings of the current study are best explained by Relational Frame Theory. The implications of these findings for teaching children with ASD and other developmental disabilities, and also teaching in general are discussed.