The study aimed to know The Level of Performance of Science Teachers in the Sultanate of Oman in Light of NSTA Standards from their Point of View. The study sample consisted of (126) science male and female teachers in the al-dakhliah governorate in the Sultanate of Oman for the academic year 2016/2017. The researchers developed a questionnaire to determine the level of performance of science teachers in light of NSTA standards, which consisted of 83 paragraphs divided into five standards. The results of the study indicate that the level of performance of science teachers was moderate. The results indicated that the highest level performance of science teachers was in teachers' knowledge and understanding of content, followed by the standard of understanding how students learn and use different methods to develop their knowledge. While the lowest level of performance of science teachers in the effective planning of educational units standard. The results also showed no significant differences in the performance of science teachers attributed to the gender variable or specialization variable, while there are differences of statistical significance attributed to the variable qualification scientific and for the benefit of Masters, and the existence of differences of statistical significance attributed to the variable number of years of service and for teachers who have years of experience more than ten years.