In this paper, the growth of telecommunications and the role of the regulator in that growth are discussed against defined parameters of accessibility, affordability and quality of service in the case of Kenya. The analysis also extends to the nature and patterns of regulation in other East African countries such as Tanzania and Uganda. The two main research question poised in this study are (1) examining the effectiveness of agreed parameters for assessing regulatory impact in the telecommunications sector and (2) independence of regulators from institutions that established them in the first place, and its impact on their effectiveness. The study also intends to examine how interventionist should regulators be in sector policy formulations such as driving a development agenda in telecommunications. The paper also explores the link between regulatory effectiveness and the national policy framework within which regulation has to operate. This paper discusses the impact or Regulation on the growth and development of the telecommunications sector in Kenya since the establishment of an independent regulator in 1999. Most of the data are collected through a primary survey and based on comparisons made with experiences of other East African countries such as Uganda and Tanzania. Section 1 discusses the theoretical underpinnings of reform and regulation in the telecommunications sector. Section 2 of this paper reviews the macroeconomic experiences of Kenya in general and telecom sector reform in specific in a comparative framework with Uganda and Tanzania. Section 3 provides an impact assessment on regulatory performance in the telecommunications sector. Section 4 discusses issues related to growth and competition followed by a conclusion.