The aim of this experiment was to determine if the joint Simon effect is modulated by group cohesion. Participants were recruited from interactive and coactive sports teams; interactive teams were assumed to have higher levels of cohesion than coactive teams. A go/no-go Simon task was completed alone (individual) or alongside a teammate (joint). Participants also completed the Group Environment Questionnaire (GEQ), a measure of cohesiveness. Each group's reaction times (RTs) were entered into separate 2-way repeated measures ANOVAs. The coactive group showed a main effect for Compatibility, F(1,15)=9.388, p=0.008, only. The interactive group showed no significant main effects or interaction. An independent samples t-test revealed that the GEQ scores of the two groups were not significantly different, t(24)=0.292, p=0.773. Consequently, an additional analysis was performed. All participants were ranked in order of their GEQ score. Those above the median were classified as "high cohesion", those below as "low cohesion". The GEQ scores of these two groups were significantly different, t(24)=-5.054, p<0.001. Two separate two-way repeated measures ANOVAs now revealed no main effects or interaction for the low cohesion group. In contrast, there were main effects for Context, F(1,12)=7.375, p=0.019 and Compatibility, F(1,12)=6.141, p=0.029 as well as a significant interaction, F(1,12)=7.387, p=0.019. These results showed that the joint Simon effect was only observed in the high cohesion group and not the low cohesion group. We conclude that it is one's GEQ score that has a modulatory effect on task co-representation, not the type of team (interactive or coactive) one belongs to.