In Korea, chaebol means a business group consisting of multiple affiliates owned by the owners and their families, and whose control is effectively vested in the owner. It also accounts for a significant portion of the national economy. In Korea, it was widely recognized that their existence and activities negatively affect the formation of a competitive market structure, and it is difficult to effectively respond to it only by regulations of competition restraints in individual markets. Based on this perception, the Monopoly Regulation Act, a competition act in Korea, introduced regulations on chaebol in 1987. This regulation focuses on restraining the expansion of chaebols through regulation of holding companies, regulation of equity acquisition, and regulation of unfair transactions between affiliates. Positive and negative views have conflicted on this regulation. However, it can be understood that there is still a minimum agreement on the necessity of regulating chaebols. The future task is to minimize the problem of excessive regulation that limits the free activities of companies and to improve it in a direction consistent with competition policies.