Display omitted •Alloyed NiCo catalysts outperform monometallic Ni and Co in activity and stability.•Ni is more selective than Co towards CH4 cracking and CO2 activation.•Co is more selective than Ni toward the Boudouard Reaction. Nickel and cobalt-based catalysts are very promising candidates for the dry reforming of methane, but their role in regulating catalyst selectivity has thus far been overlooked. Here we report the significant impact that catalyst selectivity has on the performance of Ni and Co catalysts for the dry reforming of methane. The role of Ni and Co in defining catalyst selectivity was examined via in-depth investigations into the tendency of catalysts towards the Boudouard, methane cracking and reverse water gas shift side reactions. Decoupling the side reactions demonstrated that Co deposits have a high affinity for the removal of carbon species via oxidation, while Ni is more active towards CH4 decomposition. Thereby superior catalytic performance is accessed via a combination of the high activity of Ni towards CH4 with the stabilising effect and carbon-resistance of Co. Characterisation of the materials illustrated the formation of well-dispersed NiCo alloys on the FSP-alumina, with the resulting strong bimetallic interactions fuelling enhanced catalytic performance via suppression of catalyst selectivity of Co towards the Boudouard reaction and Ni towards methane cracking.