By using a qualitative content analysis, the paper considers the research question: What explains the Middle East Quartet’s mediation (in)effectiveness in the Israeli-Palestinian conflict?. In order to answer this question, the level of MEQ’s actorness is analysed and operationalized by using Klose’s (2018) interactionist role theory with a conventional social constructivist ontology as defined by Wendt (1992) and Finnemore and Sikkink (2001). The level of actorness is then combined with examining the mediation effectiveness of the Middle East Quartet in the Israeli-Palestine conflict to see if actorness explains the mediation (in)effectiveness. Theoretical framework for analysing the mediation effectiveness is the one suggested by Herrberg (2018) – ‘seven virtues’. It is concluded that actorness does not explain the Quartet’s mediation ineffectiveness in the Israeli-Palestinian conflict since no direct relation between the two variables is found. The study suggests that the field of International Relations should be more global and instead of focusing on European mediation only, other actors should be involved, for example the Middle East Quartet.