Studies have revealed that libraries and related information institutions have not actually imbibed the culture of mentoring. This study investigates mentoring as a catalyst for career growth of librarians in Nigeria. This study adopts a convergent parallel method to combine the survey and narrative designs. The populations of this study are thirty (30) PhD holders in LIS in Nigeria and two (2) eminent professors of LIS in Nigeria. Network sampling was used to select five (5) respondents from each of the six (6) Nigeria’s geo-political zones, while convenience sampling was used to select the professors. Questionnaire and structured interviews were used to gather data from the respondents. Out of the 30 responses expected, only 29 were duly filled, submitted and appropriate for analysis. Findings revealed that the types of mentoring contributing to career growth of librarians in Nigeria are mentoring, making the roles of mentoring crucial to the career growth of the respondents.