Abstract: A retractable bayonet that can be removably coupled to a firearm or used alone. The retractable bayonet includes a housing having a first side, a second side, an internal channel, a slot having first and second ends, and first and second opening; a blade configured to be displaced between a retracted position and an extended position along the internal channel within the housing; and a fastener secured to the blade and configured to slidingly engage with the slot. When the blade is in the retracted position, the fastener is positioned at the first end of the slot and engaged with the first opening. When the blade is in the extended position, the fastener is positioned at the second end of the slot and engaged with the second opening. With one-handed operations, the bayonet can be extended or retracted when not in use.