Today's world and the conditions of rapidly changing information and technologies result in the emergence a lot of uncertainty, indefiniteness, relativity, and the available knowledge does not always help to find answers to arising questions; thus, the employee himself has to make the decisions that best suit the existing situation. In order to respond to the relevant issues of education, teachers are required to continually improve, flexibly responding to emerging teaching and learning situations, combining theoretical knowledge and experience gained in practical activities. Reflective practice using reflection as careful consideration of one's activity in order to improve it is an effective way of teachers' personal and professional development, promoting to integrate theory and practice, develop a personal theory of education, and strengthen one's as professionals' self-awareness. The formulated problem question of the research is: How can reflective practice help the teacher to improve personal and professional competencies? Applying the methodology of content analysis of scientific literature and qualitative research, it was found that the teacher who deliberately and purposefully applies reflective practice consistently develops personal and professional competencies. Systematic reflective practice helps the teacher to know himself, his strengths and areas of improvement, notice differences between activity before reflection and the structurally considered process. Developed reflection skills enable to flexibility respond to nascent situations, create education-friendly environments, observing and reflecting on ongoing activities. Learning from one's activity by planning, observing it and reflecting on it promotes to know pupils, simulate the educational process and form one's teaching style, choosing the methods that are the most suitable for pupils, focusing on pupils' engagement and development of their reflection skills. Purposeful and consistent reflective practice develops personal and professional competencies, promotes the teacher's growth.