There are disagreements about the key factors affecting a line manager’s conflict management modes. Psychologists emphasise the role of the conflict situation and personal traits, while other scholars focus on the impact of organisational aspects in managing interpersonal conflict. This paper provides empirical evidence suggesting that three sets of factors, namely, situational, personal and organisational aspects, influence the mode of handling conflict by line managers. Mixed methods were used to collect primary data from 19 line managers and two human resources managers working in two Irish subsidiaries of multinational companies. Although the research design did not allow for a verification of whether each of those three sets of factors has a significant influence on managing conflict by line managers, the paper suggests that combining psychological and managerial approaches to managing conflict provides a fuller understanding of handling interpersonal conflict. It also provides original findings on how line managers handle interpersonal conflicts, contributing to a better understanding of the under-researched area of the actual role of line managers in dealing with negative HR aspects.