Projects are undertaken with the end goal of getting completed someday. Project completion is a collective responsibility among the parties involved. The dilemma and struggle for project completion is a concern in the 21st century. The study intended to find out possible effect of scope changes on project completion among road construction projects in Nairobi County with a distinct case of Langata Sub county. The key variables for the study were; project regulatory compliance changes, project technological changes, project objective changes, as well as project stakeholders’ changes. These variables were used to help determine and make informed decisions on the effect of project completion. The viability of the variables was verified through subjecting them into the theoretical literature reviews. The theories for determining project completion against the supreme variables involved: Contingency theory and Theory of Constraints (TOC). The study engaged descriptive research design and methodology techniques that enhanced data collection procedures and analysis for effective and reliable findings to the effect of project completion. The study anticipated to solve the menace of scope changes on project completion among road construction projects in Nairobi County, Langata Subcounty. Data was collected through a structured questionnaire in Langata Subcounty. The respondents provided relevant and useful information based on the research questions that were asked. It is through such information that informed decisions from the findings were made regarding the effect of scope changes on project completion among road construction projects in Nairobi County and recommendations deduced. The recommendations indicated clearly that project completion is a collective responsibility among the parties involved. The data gathered was analyzed using the Statistical Package for Social Sciences (SPSS) version 25. Descriptive statistics such as; frequencies, percentages, mean and standard deviation were conducted. In addition, correlation statistics, regression analysis was used to test the relationship between the dependent and independent variables. The study was therefore viewed as a tool and a guide in determining the effect of scope changes on project completion among road construction projects across the country. The research project used a target population of 350 Licensed Road Contractors and Supervising Engineers. The research project adopted a Nassimas formula that arrived at a sample size of 78 respondents. From the findings, only 53 response rate was obtained representing 67.9% which was considered to be very good for analysis. Findings were presented in figure and table form, explained and summarized as well as recorded on a five-point Likert scale anchored on strongly disagree (1) to strongly agree (5). Recommendations were made to project managers, licensed road contractors, construction professionals, project developers, National and County Governments to use findings of the study to realize project completion.