This study investigates the teachers’ collaboration for school improvement and performance in Caibiran District, Philippines. Employing the descriptive-correlational survey method with 68 elementary teachers served as the respondents of the study. On the level of teachers’ collaboration, most of the respondents have agreed on the following: shared beliefs, values and vision, shared and supportive leadership, collective learning, support conditions, shared personal practice, leadership characteristics, normalizing classroom practice and supporting teaching collaboration. With regard to the problems and issues encountered by the respondents during teachers’ collaboration, most of the respondents had problems and issues on lack of cooperation/teamwork, teachers have different ideas/opinions on a certain topic that makes the work more complicated, lack of time and lastly on creating unhealthy competition among teachers. On the effects of teachers’ collaboration to school improvement, the number of enrolment has decreased for the last three years. Repetition rate has also decreased and promotion rate reveals an increasing rate for the school year 2015-2016 and 2016-2017 but most of the schools do not have the data for the school year 2017-2018. With regard to the school improvement status for the last three years, the academic performance based on the MPS of each schools in Caibiran district are on the category of moving towards mastery. This shows that teachers did not do their very best so that the school could attain the ‘mastered’ rating to improve their school performance.