[en] In this report, we present nanoelectromechanical resonators fabricated with thin exfoliated crystals of a high-T _c cuprate superconductor Bi₂Sr₂Ca₁Cu₂O. The mechanical readout is performed by capacitively coupling their motion to a coplanar waveguide microwave cavity fabricated with a superconducting alloy of molybdenum–rhenium. We demonstrate mechanical frequency tunability with external dc-bias voltage, and quality factors up to  ∼36 600. Our spectroscopic and time-domain measurements show that mechanical dissipation in these systems is limited by the contact resistance arising from resistive outer layers. The temperature dependence of dissipation indicates the presence of tunneling states, further suggesting that their intrinsic performance could be as good as other two-dimensional atomic crystals such as graphene. (paper)