The professional development and performance of teachers in Kicukiro District are very important to ensuring quality education. Despite the responsibilities outlined in the Teachers' Act, including attendance at classes, lesson planning, and student assessment, the report found that there are gaps, particularly in relation to absenteeism and planning. These problems are a threat to student achievement and school performance and show a great need for research and strategies to improve teacher performance. The aim of this study is to examine previous implementations of professional development programs, assess their impact on teaching skills, teaching methods, and subject knowledge, and identify potential barriers to their effective implementation. Through a descriptive correlational research design, primary data were collected through questionnaires, and secondary data were collected through document analysis by selecting 15 principals and 435 teachers. Data analysis included descriptive statistics, correlation, and analysis using SPSS version 22.0. The correlation analysis of the variables showed a significant relationship between the different factors. For example, there is a significant positive relationship between teacher training and effective teaching practices (r = 0.611, p < 0.01), students’ performance (r = 0.940, p < 0.01), and teacher professional growth (r = 0.890, p < 0.01). Likewise, undergraduate and short courses are positively correlated with effective teaching (r = 0.598, p < 0.01), student performance (r = 0.552, p < 0.01), and teacher professional growth (r = 0.550, p < 0.01). Continuing professional development (CPD) has a significant positive relationship with effective teaching practices (r = 0.732, p < 0.01), student engagement (r = 0.431, p < 0.01), and teacher professional growth (r = 0.469, p < 0.01). In addition, seminars were positively correlated with effective teaching methods (r = 0.255, p < 0.01), student performance (r = 0.496, p < 0.01), and teacher professional growth (r = 0.521, p < 0.01). These results indicate that these training and development activities are associated with improved teaching practices, student outcomes, and teacher professional growth. Finally, the research highlighted the importance of CPD for teachers and their job satisfaction. The research recommended that the government should invest in supporting teachers and schools in providing the training and resources that are needed for teacher development, hence the performance.