The tittle of this work is A Linguistic Study of Loan Words in Nigerian Pidgin. Researches have shown that Nigerian Pidgin (NP) is a Nigerian language and clearly different from other varieties of West African Pidgins. Pidgins are known to have small vocabularies which continue to expand to fulfill the linguistic needs of their users. Nigerian Pidgin is no exception. This work sets out to identify the sources of the words that came into NP. Data for this research were got from two sources - a book â€-Sozaboyâ€- (1985), which is a relatively earlier variety of NP, and news scripts from three NP using radio stations (2015): the latter is a relatively current variety. A questionnaire listing words got from our data was administered to NP speaking ABU students, and the respondents were required to provide or confirm the sources and meanings of the words. The responses were analyzed using Serjeanston and Erik Bjokman's models. The findings reveal that specific languages have contributed to the vocabulary of NP, and that a difficulty exists in identifying the real provenance of every linguistic item. The findings, while maintaining that English is the initial lexifier language, show that words from other languages have come into NP. This research goes further to prove that NP is like any other natural language in active use, in that it has borrowed and continues to borrow to swell its initially small vocabulary.