This study investigated the relationship between librarians’ professional development and effective service delivery in federal university libraries in South-South Nigeria. A correlational survey research design was adopted. The population comprised 110 librarians from seven federal university libraries in the South-South geopolitical zone of Nigeria, and the total enumeration sampling technique was adopted to select all 110 librarians. Data were collected using a structured questionnaire titled
Aderonke Aderonke (Mon,) studied this question.