The present disclosure concerns embodiments of a folding knife having a locking mechanism for locking a blade in open and/or closed positions. The locking mechanism a first locking element on the blade and a corresponding second locking element on the handle that is adapted to engage the first locking element when the blade is in open and/or closed positions. The blade can be mounted on a leaf spring in the handle for pivotal movement relative to the handle between the open and closed positions. The leaf spring functions to support the blade and provide a biasing force that resiliently biases in a direction laterally toward the second locking element on the handle.