Kenya is undertaking public procurement reforms, by enacting the Public Procurement and Disposal Act (PPDA) of 2005 which became operational in 2007. This research considered the factors which affect the implementation of PPDA in public secondary schools by considering four factors; procurement skills, enforcement, organizational procurement culture and familiarity with procurement regulations. The researcher adopted purposive sampling and questionnaires were administered to the respondents, who included the members of the tender and procurement committees. Data collected was analyzed by use of SPSS and presented in percentages, frequency tables, and inferential statistics. The study showed that there is a significant relationships between; procurement skills, enforcement of PPDA, organizational procurement culture and familiarity with the regulations and the implementation of the PPDA. 80% of the respondents agree that lack of familiarity with the procurement regulations, inhibited the implementation of the PPDA. 85% of schools in Trans- Nzoia County have not engaged procurement professionals. 53% of the respondents agree that lack of training has hindered the implementation of PPDA. 80% agree that lack of enforcement has somehow hindered its implementation. It is recommended that the procurement officers in public secondary schools to read, understand and implement the Public Procurement and Disposal Act 2005 and that the school management should train their procurement officers to gain procurement skills, which will enhance the effective implementation of the PPDA.