We created and evaluated a professional development package for training four teachers to embed instructional interactions during outdoor time to enhance the play skills of young children with significant developmental disabilities. The instructional package included an initial 20-min session that consisted of providing written and verbal instructions, modeling, and rehearsal with feedback. Following the initial training session, we provided teachers with self-monitoring cards to guide their interactions and with feedback (i.e., coaching) on their performance. Researcher involvement was faded over four sessions. Results indicated that teachers increased and maintained their instructional interactions with targeted children after receiving the professional development package. Children's engagement in outdoor play served as a collateral outcome measure and revealed improvement. Supplemental probe data were gathered by an unobtrusive recorder to assess observer reactivity and maintenance of teacher performance in the absence of the primary observer. These unobtrusive observations were inconclusive but suggested a potential effect attributable to reactivity. (author abstract)