The construction industry in Pakistan is experiencing a surge in public sector projects due to major investments in infrastructure projects. Project delays and cost overrun are common features in public sector construction projects in Pakistan. Therefore, an understanding of the causes of time and cost overrun in public projects is essential. This paper investigates delay and cost overrun factors within the context of public sector projects in Pakistan. This study identifies 48 potential factors from existing literature and semi-structured interviews were used to refine the identified factors into ten categories. A questionnaire survey was used to establish a hierarchy of factors using descriptive statistics. The results showed that the major causes of time overruns in public projects were (1) legal issues, such as court stay orders, land acquisition, relocation of public facilities; (2) technical errors leading to low-quality drawings, rework, and errors at bidding stage; and (3) Poor project management. The findings of this research contribute to understanding the causes of project delays in public sector projects in Pakistan.