The Doctoral Thesis “Governance of the Owner-managed Small and Medium-sized Enterprises” is developed in Latvian and consists of an introduction, four chapters, conclusions and proposals, a bibliography and five annexes. Chapter 1 of the Doctoral Thesis explores and analyses the concepts of small and medium-sized enterprises and the owner-manager of the enterprise, the contribution of such enterprises to the economy and how understanding of these concepts has changed over time. A new typology of SME owners-managers, consisting of 10 types of SME owners-managers is developed and proposed. Chapter 2 explores SME governance issues from a systemic approach perspective. Particular attention is paid to the governance of owner-managed companies. At the end of the chapter, governance practices in three owner-managed small and medium-sized enterprises are compared on the basis of findings from theory and previous studies. Chapter 3 describes the empirical study conducted on the owner-managed SMEs, the methodology of the study and the results of statistical analysis of the study data, cluster analysis and visual analysis of the results of the governance self-assessment. Chapter 4 of the Doctoral Thesis develops and describes a methodology by which owners and managers of small and medium-sized enterprises can analyse and improve their business, as well as recommendations on how this approach can be used in the process of training and professional development of managers. The volume of the Doctoral Thesis is 152 pages and 17 pages of annexes. The Thesis includes 31 figures, 30 tables and 5 annexes illustrating and explaining the content of the work. 123 sources of information in Latvian and English have been used for the development of the Doctoral Thesis.