The theme of the Promotion Thesis is “Intellectual capital management and development in companies in Latvia”. The Promotion Thesis has been elaborated at the Institute for Quality Engineering of the Faculty of Engineering Economics and Management at Riga Technical University. The first part “Theoretical aspects of intellectual capital formation” discusses the formation of intellectual capital, showing its transformation from resource to capital. The author analyses different views on intellectual capital and related concepts, interrelationships between the concepts. The definition of intellectual capital is refined and a new structure of intellectual capital is prepared. This section also explores the views on investments in intellectual capital in the scientific literature, the author analyses the intellectual capital development tools, as well as their nature and types. A definition of investments in intellectual capital is prepared. In the second part “Intellectual capital and its development trends in Latvian companies”, the author analyses intellectual capital and its development dynamics in Latvian companies. This part contains the results of the author’s empirical study, which aimed to identify the importance of intellectual capital and investments in intellectual capital in the company, factors affecting investments at the enterprise level in Latvia, as well as to determine the expected results from investments. The third part “Intellectual capital development to ensure company sustainability” is designed as a presentation of solutions and recommendations for the company’s intellectual capital development proposed by the author. For the development of intellectual capital with the help of investments, the author offers a classification of these investments according to the company’s functional sphere and time. The author has created an approach to designing intellectual capital development strategy that is based on the integrated management system and the holistic approach. The Promotion Thesis contains introduction, 3 chapters, Conclusions and Recommendations, Sources of Reference, as well as 9 Appendices. Total scope of the Promotion Thesis is 167 pages. The Thesis contains 31 figures and 49 tables. The Sources of reference contain 208 sources.