Literacy is undeniably the catalyst as well as the anchor of any nationâ€™s development hence, a strong correlation between the literacy level and the socio-economic status of any nation. Regrettably, illiteracy rate in Nigeria is alarmingly high, based on the revelation of the Federal Minister of education in 2017 that nearly 65 to 75 million Nigerians are Illiterate. The Library is a veritable instrument for literacy crusade, being an information and educational resource eminently and conspicuously positioned to promote literacy through inclusive library and information services. This paper dwells on the relevance of the library in literacy promotion in Nigeria. It also spotlights the roles of the library in promoting literacy. The paper irradiates some challenges libraries and library professionals face with regards to literacy promotion as well as proposing ways forward.