The　micromechanical　behavior　of　(CoCrNi)94Al3Ti3　medium-entropy　alloy　(MEA)　with　and　without　Al2O3　nanoparticles　was　investigated　by　nanoindentation,　microhardness,　and　microscratch　tests.　Adding　Al2O3　nanoparticles　in　the　(CoCrNi)94Al3Ti3　MEA　increases　elastic　modulus,　hardness,　brittleness,　and　friction　coefficient.　The　MEAs　with　and　without　Al2O3　exhibit　indentation-induced　pile-up,　resulting　in　the　inapplicability　of　the　Oliver　&　Pharr　method.　The　elastic　modulus　and　indentation　hardness　were　assessed　by　the　work-based　approach.　Indentation　size　effect　is　observed　for　the　MEA,　but　is　absent　with　the　addition　of　Al2O3　nanoparticles.