This comparative study examines the moderating role of risk management in project planning and project success in the construction business of the UK and Pakistan. The data was gathered from 152 project managers (76 from both economies each) using a survey questionnaire. The purposive sampling technique was used to ensure fair representation of sample size and the RAND formula was used to select the project managers. For quantitative analysis, partial least square structural equation modelling technique was utilised. The results confirmed that project planning had a statistically significant impact on project success. Furthermore, risk management significantly moderated the relationship between project planning and project success in the construction businesses despite being in two different economies. The paper contributes to the enhancement of the body of knowledge intended for global companies and academicians aiming to implement risk management frameworks to enhance project success and ensure the effectiveness of project planning in a competitive business environment. It offers a new perspective to investigate the relationship between project planning and project success through moderating the effect of risk management, which is a new theoretical dimension for construction business and the field of project management. It is proposed to the governments and construction businesses operating in the UK and Pakistan to validate the empirical research framework in the cross-cultural context while assessing risk and uncertainty. It helps the construction business in the evaluation of risk while planning and successfully implementing project strategies.