This study examined unethical favouritism and knowledge hiding (KH) to ascertain the extent to which unethical favouritism influences KH as well as the extent to which organisational injustice mediates the relationship between unethical favouritism and KH. The study employed a cross‐sectional survey design of 305 randomly selected respondents from one public and four private universities in northcentral Nigeria. A structured questionnaire served as the research instrument. The study used the Content validity index and Cronbach alpha to test for the validity and reliability of the questionnaire. Structural equation modelling served as the data analysis technique. The results indicate that unethical favouritism significantly influences KH, and organisational injustice mediates the relationship between unethical favouritism and KH. The point of departure of this study from previous studies is the unveiling of the influence of favouritism on KH through the mediation of organisational injustice, which is a consequence of favouritism.