The problem addressed in this study was high school science teachers' lack of understanding of science, technology, engineering, and mathematics (STEM) and clarity for the integration of Next Generation Science Standards (NGSS) approaches to align standards in STEM with high school science education. The purpose of this qualitative case study was to examine how high school teachers incorporate science and engineering practices, crosscutting concepts, and disciplinary core ideas to enhance students' acquisitions of STEM skills. This study used surveys and semi-structured interviews to gather data from high school science teachers in the Washington, D.C., metropolitan area. Data collection consisted of surveying 15 high school science teachers, responding to demographic and Likert scale (five point) questions on teachers' perceptions, and open-ended semi-structured interviews with 10 high school science teachers. The findings indicated that school districts should provide teachers resources to implement the NGSS in the curriculum at their schools. Also, the results revealed that there was a need for more professional training for science teachers to properly implement the engineering activities and NGSS in their science classes. Several of the science teachers noted that professional development and technology resources were needed to integrate NGSS are available in their classrooms. The findings revealed that science teachers would like their school district to provide more resources to implement and reinforce STEM skills across the curriculum. Implications were that educational benefits of NGSS include, but are not limited to, the shifts interconnecting science and engineering practices, disciplinary core ideas, crosscutting concepts, recognizing learning progressions, including engineering, addressing the nature of science, and coordinating with Common Core State Standards. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]