Enhancing the performance of administrative staff necessitated this study. The study quantitatively analyzed the influence of affective commitment on the job performance of administrative staff in tertiary institutions in Anambra State. One research question and one null hypothesis were tested at a 0.05 significant level, guiding the study. The study adopted a descriptive survey research design with a population of 544 administrative staff in tertiary institutions in Anambra state studied without sampling. A 10-10-item questionnaire titled "Influence of Affective Commitment on the Performance of Administrative Staff (IAC-PAS)" was used for data collection. The face and content validity of the instrument were determined by two experts in business education, measurement, and evaluation. Trail testing was used to establish the instrument's reliability, and data were analyzed using Cronbach alpha reliability, which yielded a coefficient value of .81. The researchers, with the help of three research assistants, administered copies of the questionnaire to the respondents. Out of the 544 copies of the questionnaire distributed, 528(97%) copies were correctly filled and returned and used for data analysis. Statistical mean and standard deviation were used to answer the research question and determine the homogeneity of the respondents' ratings, and a t-test was used to test the null hypothesis. Findings revealed that administrative staff agree that affective commitment influences their performance in tertiary institutions in Anambra State. Age did not significantly influence respondents' mean ratings on the influence of affective commitment on the performance of administrative staff in tertiary institutions in Anambra State. Based on the study's findings, the researchers concluded that building a working environment that promotes affective commitment can improve the performance of administrative staff of tertiary institutions in Anambra State to a very high level. Therefore, it was recommended that the management of tertiary institutions in Nigeria provide regular organizational support programs for administrative staff to better develop their personal and career objectives and improve their affective commitment and job performance.