Coadsorption of CO and O over five metal (111) surfaces under strain has been computationally investigated, which is relevant to key catalytic processes like CO oxidation. Strain sensitive/insensitive metals with respect to O and CO adsorptions are identified. For strain sensitive metals like Pd and Pt, the effects of strain and coadsorbates can be utilized to tune their catalytic performance, providing a new perspective on solving the problems of CO poisoning. For strain insensitive metals like Rh, Ir, and Cu, both effects are much weaker. Overall, the synergistic effect of coadsorbates and strain should be further investigated for catalyst design.