We apply a social identity perspective to study third party`s strategies, a general and established form of intervention, consisting of a set of tactics or specific, measurable behaviors in the context of a strategic line (Wall, Chan-Serafin & Dunne, 2012), behaviors in the context of the relevant strategic line outside of which would have no meaning or purpose (Lim & Carnevale, 1990; Serrano, 1999). Using an observational approach this research examines the influence of the social identity and type of labour conflict on mediation strategies. Our theoretical framework suggests how third party`s strategies can be used in mediation systems differentiated into ingroup (group to which third party belongs) and outgroup (group to which third party does not belong) in two type of conflicts in the context of employment relations, interest and rights disputes (Devinatz & Budd, 1997). We demonstrate the role of third parties`s strategies in conﬂict revealing that mediation is more effective when the disputants don’t share some aspect of their identities with third parties irrespective of types of conflicts, at the same time, we observed that mediation is more effective in interest based conflicts than right based conflicts irrespective of third parties’s affiliation. We found that third parties from ingroup use less contextual and reflexive and more substantive strategies compared with third parties from outgroup in both, interest based conflict and rights based conflict. Implications for conﬂict management are discussed.