A selectable one-way clutch to selectively enable torque transmission only in one direction and to interrupt torque transmission in both directions is provided. The selectable one-way clutch comprises: an oil passage that is formed in the selector plate, and that has a first opening situated at a lower level than the oil level and a second opening situated at a higher level than the oil level; and a closure that is formed on the pocket plate at a position to close the second opening at least partially when the selectable one-way clutch is in the overrunning mode, and to increase the opening area of the second opening when the selectable one-way clutch is in the engagement mode.