Training is practical instruction in job and task requirements and methods. It may be provided at workplace, and its objective is to enable workers to meet some minimum performance standards or to maintain their proficiency. Performance is the means by which workers demonstrate that they have understood the training and can apply it in practical situations. The problem under study was that, many public primary school teachers in Kenya enroll for different trainings yet the performance of public primary schools remains dismal in national examinations and hence the study entailed establishing the influence of training on performance of public primary school teachers in Teso South Sub-county of Busia County. The main objective of the study was to establish the influence of training of public primary school teachers on their performance. The specific objectives of the study included; establishing the relationship between knowledge and performance of public primary school teachers, establishing the effect of skills on performance of public primary school teachers and establishing the effect of commitment on performance of public primary school teachers in Teso south sub-county of Busia county. The study was guided by, Adams equity theory, Vroom’s expectancy theory and Kirkpatrick’s learning and training evaluation theory. The study was conducted in Teso south sub-county of Busia county, Kenya. The target population comprised one thousand and twenty four public primary school teachers of Teso south. The study applied a survey research design. The sampling technique used was multistage sampling technique while the sample size was (288) two hundred and eighty eight teachers which was determined using the Yamane’s (1967) formula. Questionnaires which had a validity index of 0.55 and a reliability index of 0.82 were used as the instrument for data collection. Quantitative data collected was analyzed using descriptive statistics while qualitative data from open ended questions were analyzed using thematic analysis. The study found out that majority of the respondents had the view that an employee’s knowledge increased with training,74% of the teachers were of the view that their skills had increased with the trainings they had been exposed to while a majority of respondents held the view that training improved commitment of the teachers. The study concluded that training influenced performance positively. The study recommended that the teachers should be continuously exposed to training opportunities to enable them to gain more knowledge, skills and commitment levels required to catapult their institutions to higher levels of performance. The significance of the study is that it would help educational stakeholders know the amount of investment needed in teacher’s training and the expected outcome variables based on research findings of the study.