The current study aims to reveal the perceptions of science teachers about the difficulties of implementing the STEM integrated approach in the Sultanate of Oman, according to gender and teaching experience variables in science. To achieve the objectives of the study, the descriptive approach was used and a questionnaire was used as a data collection tool. It consisted of three parts. They are: difficulty related to the teachers in implementing the STEM approach and included 13 items, difficulties related to the learning environment and included 11 items, and difficulties related to the content that included 12 items. After verifying the validity and its reliability, it was applied to the sample of the study which was chosen purposively. The sample consisted of 117 science teachers in the Sultanate of Oman, applied STEM in their schools. The findings showed that teachers' perceptions of STEM-related difficulties were high. Where the third part (difficulty related to content) ranked first with an average of 3.51 with a degree of great difficulty. Followed by the second part (difficulty related to the learning environment) came in second place with an average of 3.31 with a degree of medium difficulty. Then, the first part (difficulty related to the teacher) with an average of 2.77 with a degree of medium difficulty. Also, there were differences of statistical significance due to the variable of teaching experience, for the second group (more than 10 years), and the absence of statistically significant differences due to gender variable. In the light of these findings, the study recommends that the content of science curriculums should be developed through STEM-oriented design, to prepare classrooms and provide tools that help students to practice work associated with STEM orientation, and to develop the performance of science teachers by providing intensive training courses on the ideal application of STEM in teaching science.