This study examines how the socio‐demographic characteristics of arbitrators and of plaintiffs affect arbitrators' judgement bases for arbitration decisions. Two research questions are tested quantitatively based on a data set of arbitration decisions in the Canadian university sector collected from the website of the Canadian Legal Information Institute. We created two models of independent variables related to the socio‐demographic characteristics of arbitrators and plaintiffs. Multinomial logistic regression is used to examine the possible impacts of these variables on the justifications used by arbitrators to explain their decisions. The results indicate that both models significantly influence how arbitrators justify their arbitral decisions. The following variables significantly contribute to the models: arbitrator's age, arbitrator's professional experience in management, plaintiff's gender, and support of the plaintiff by a collective entity (union or association). Young arbitrators are more likely to use “laws” and those who have professional experience in management tend to cite “evidence” to justify their arbitral decisions. Also, arbitrators are more likely to use “evidence” as their judgement basis for male plaintiffs who are supported by a collective entity. The details of these findings, limitations of the study, and future directions for research are further discussed.