The study investigated the impact of organisational factors on job performance of librarians in university libraries in Delta and Edo States, Nigeria. Two research questions guided the study. Descriptive research design was adopted, with a population of 140 librarians from university libraries in Delta and Edo States. The total enumeration sampling technique was employed. Data were collected using a questionnaire titled ―Impact of Organisational Factors and Job Performance of Librarians in University Libraries Questionnaire (IOFJJPOLIULQ).‖ Data analysis was conducted using descriptive statistics (frequencies, mean, and standard deviation) to address the research questions, with the decision rule based on mean scores. The findings revealed that various organizational factors have a significant impact on librarians' job performance in university libraries in Delta and Edo States. Job performance level among librarians was found to be high. The study concluded that organisational factors play a crucial role in determining librarians' job performance in the states. High job performance level suggest that these organisational factors are likely well-implemented, positively contributing to librarians' roles and overall effectiveness. Recommendations included investing in continuous training and development programs for librarians; that ongoing professional growth opportunities will enhance job performance, increase job satisfaction, and improve retention rates. The study contributes to the knowledge base by demonstrating that organisational factors such as a positive work environment, library facilities, leadership styles, technology provision, and opportunities for advancement can influence job performance in libraries.