The purpose of this study was to investigate science teachers’ self-regulated teaching practice in secondary schools and the relationship between school factors and self-regulation using teaching self-efficacy belief as mediator in South Gondar zone. An explanatory sequential mixed method with co-relational survey design was applied. The participants were 302 science teachers (chemistry, biology and physics) from the total 63 secondary schools only 9 were selected using random sampling method. The 302 participants were selected using comprehensive sampling. Descriptive statistics, t-test (both one sample and independent), multiple regressions and structural equation modeling were used for quantitative data analysis; thematic transcription and interpretations analysis were used for qualitative data. The quantitative results indicate that teachers of the study area reported as they are implementing self-regulated science teaching. The interview analysis result also confirms that teachers perceived as they are implementing self regulated teaching with low conceptual understanding and knowledge of self-regulation. The descriptive statistics explained that teachers implement preparatory phase of self-regulation more than performance and reflection phases. But, the qualitative result shows somewhat differently in which half of the participant’s lack planning and selecting strategies from preparatory phase and implementing performance and reflection phases better than preparatory phase. The multiple regression analysis result shows that teachers’ gender and teaching experience were not found significant predictor of self-regulated teaching; however, the independent sample test and qualitative data identify that female teachers are more effective than their male counter parts in their self-regulated science teaching. Moreover the structural equation model analysis result informs that among school factors, only professional learning community practice (PLC) was found to have a significant positive effect on self-regulated teaching both directly and indirectly. Science teaching efficacy belief plays its meditational role in the relation between PLC and SRT but not for science teaching resource availability (STRA) and SRT. Other researchers who are concerned on the issue are recommended to conduct an experimental research and its effect on students’ outcome to show its significant impact on teachers’ teaching effectiveness and to conduct an instrument validation study. Self-regulated teaching concept would bring teaching quality of teachers if incorporated in their training system. Results’ implications are indicated in chapter 5.