A search for CP violation in Cabibbo-suppressed D±→ K0 SK±and D± s→ K0 Sπ±decays is performed using pp collision data, corresponding to an integrated luminosity of 3 fb-1, recorded by the LHCb experiment. The individual CP-violating asymmetries are measured to be (Formula presented.) assuming that CP violation in the Cabibbo-favoured decays is negligible. A combination of the measured asymmetries for the four decay modes D± (s)→ K0 SK±and D± (s)→ K0 Sπ±gives the sum (Formula presented.). In all cases, the first uncertainties are statistical and the second systematic. The results represent the most precise measurements of these asymmetries to date and show no evidence for CP violation.