Urban management institutions control spatial activities in cities. Realisation of this role through the instruments of physical planning, depends on the outcome of the implemented planned activities. Existing literature has substantially examined the problem of plan implementation in a generalised outlook, with little empirical investigation on critical factors contributing to plan implementation outcome. This study therefore, was carried out to investigate the role of the planning process and socio-economic characteristics of residents, on plan implementation in Abuja, Federal Capital Territory, Nigeria. Rational planning theory served as anchor for the study which guides the planning process that determines the procedural ambit of planning activity. A cross-sectional survey design was adopted and sampling design based on 194,509 total housing stock in the four development phases of the city. Out of the total stock, 973 respondents representing 0.5% in each of the development phases, were randomly selected. A self-structured questionnaire consisting of socio-economic characteristics and planning process variables were administered for collection of primary data. Descriptive statistics and Binary Logistic Regression at p< 0.05 were used for the data analysis. The results show that the effect of responsiveness to residents was significant, β = 2.039, OR = 7.68, p = .000, the effect of management of the city was significant, β = 0.646, OR = 1.907, p = .000, and the effect of how service delivery is executed was significant, β = 1.053, OR = 2.867, p = .000, while the Joint contribution is χ2 (10) = 313.83, p < .001. Responsiveness of urban management institutions, management structure and service delivery were critical factors of plan implementation. Therefore, human-centred planning policy, civic engagement and the use of smart planning tools will augur well for plan implementation.