The purpose of this study is to establish a relationship between ISO 9001:2008 certification and service quality of Kenya Plant Health Inspectorate Services (KEPHIS). The study was informed by Deming’s theory. The study adopted correlational research design. The target population was 130 respondents from KEPHIS. A sample size of 97 respondents was chosen for the study. The data collection instrument that was used to collect was questionnaires and interview schedule. The data collected were analyzed using descriptive statistics such as frequency, percentages and means and inferential statistics which included the Pearson correlation and regression analysis. The findings revealed that customer focus has a positive and significant effect on service quality. However, system approach management does not have a significant effect on service quality. The study concludes that customer focus is critical towards enhancing the quality of service of the organization. From the findings of the study, the study recommends organization under the guidance of the management to set up systems that would enhance their level of interaction with the customers