Achievement of a project means that a number of its perceived factors were attained. It is not guaranteed that project management practices will result to proper implementation of projects by manufacturing companies. However, the success of projects largely depends on the way it is managed and controlled. The challenges met during the implementation of project management practices has been during project planning, exceeding the set budget and going beyond its set schedule and poor quality. The general objective of the study was to investigate the influence of project management practices on the implementation of projects in manufacturing companies in Nairobi City County, Kenya. The study’s specific objectives were to examine how stakeholder participation, leadership support, communication and resource allocation influenced project implementation. The study was anchored by stakeholder theory, resource based view theory and cybernetics theory. The study adopted a descriptive research design. The target population was 49 manufacturing companies from the industrial area of Nairobi City County. The targeted respondents were 294 comprising of 49 project managers and 245 project team members. The study used stratified sampling method to ensure that all cases are well represented and use simple random sampling method to select the respondents. The sample size was 169 respondents. Data was collected using questionnaires and analysed using both descriptive statistics and regression analysis. The study established a positive and significant relationship between stakeholder participation, leadership support, communication and resource allocation and project implementation. The study concludes that community participation during implementation of projects in manufacturing companies is a vital as it leads to better outcomes for all stakeholders, stakeholder ownership and lower project costs. Leadership support is considered one of the critical success factors in project implementation, effective executive involvement can significantly improve project success. Maintaining open, regular and accurate channels of communication with all levels of project staff and stakeholders is vital to ensuring the effective implementation of capital expenditure projects. Allocation of resources helps managers to bring together more productive and effective project teams and workgroups and enables them to appraise their schedules and easily estimate resource availability in real-time. The study recommends that strict scrutinization of project teams to be done to ensure that all the stakeholders are well represented. This will ensure that various needs are effectively addressed. The top managers from the manufacturing companies should ensure proper planning, organizing is done according to the set objectives of the project and also lead and motivate the staff involved in the implementation of the projects. Project activities should be communicated to every party concerned during implementation of projects and the manufacturing companies should establish the right channels of delivery messages and feedback in both top-down and bottom-up communication. The management of the manufacturing companies should identify the right resources towards effective implementation of the projects.