This mixed-methods study utilized qualitative analysis and cross-tabulation, to identify differences in proportions between pre- and post-lesson plans for 16 secondary preservice general educators after having received instruction on UDL. Participants' lesson plans were qualitatively and quantitatively evaluated for the presence of UDL principles using the rubric of Spooner et al. (2007). In addition, types of strategies and tools were identified in participants' changes to post-lesson plans. The results of Fisher's exact test indicated there were no significant differences between pre- and post-lesson plan scores across the UDL principles of engagement, representation, and action and expression. Results indicated that instruction on UDL was beneficial for the 16 secondary preservice general educators in this study for developing inclusive lesson plan changes in the general education setting.