Embodiments of crimping devices for crimping stented prosthetic valves and other medical devices from a larger, expanded diameter to a smaller, crimped diameter are disclosed. Some crimping devices utilize a conical surface extending out-of-plane from the direction of crimping, where motion of the conical surface in the out-of-plane direction causes in-plane radially crimping. Other crimping devices comprise a funnel-shaped rigid body having a tapered inner lumen that compresses a medical device moving therethrough. Some funnel-shaped embodiments have slotted sides that allow portions of the medical device to project therethrough. Other funnel-shaped embodiments are used with a tubular sock to pull the medical device through the tapered lumen. Other crimping devices utilize rotating rollers that compress a medical device while the medical device spins between the rollers.