Sexual and gender minority youth (SGMY) face staggeringly high rates of verbal and physical harassment, and markedly higher suicide attempt rates. Studies have linked more positive school environments and the use of inclusive curriculum to better academic and mental outcomes for SGMY. This study investigated if a modified sex/health education curriculum with a focus on SGMs could result in a positive increase in classroom climate, and knowledge growth, and a decrease in negative attitudes towards transgender persons and attitudes towards homosexual persons as measured by surveys to determine the feasibility of the modified inclusive sex/health education lessons as a MTSS Tier 1 intervention in schools. The findings produced mixed results with qualitative findings suggesting that the modified sex/health education curriculum with a focus on SGMs had a positive relationship with classroom climate and knowledge growth. The quantitative findings in this study did not find enough evidence to support a positive increase in knowledge and/or classroom climate and/or a decrease in negative attitudes towards SGMs to support the implementation of the modified lessons as MTSS tier one intervention.