A firearm with folding buttstock comprising: a receiver; a barrel coupled to a front end of the receiver, the barrel defining a longitudinal axis and an axially extending bore forming a projectile pathway; an elongated buttstock defining a stock axis; a hinge assembly pivotably coupling the buttstock to the receiver, the hinge assembly comprising a fixed front hinge element coupled to the receiver, a movable rear hinge element coupled to the buttstock, and a hinge with hinge pin pivotably coupling the front and rear hinge elements together; the buttstock pivotably movable between an inline position, and an offset position in which the stock axis is laterally offset from the longitudinal axis; a latch pin rotatably and slideably carried transversely by the hinge assembly; a latching mechanism on a first lateral side of the hinge assembly comprising a latch member on a first end of the latch pin engageable with a latch recess on the first lateral side, the latching mechanism operable to maintain the buttstock in the inline position when the latch member engages the latch recess; a locking mechanism on a second lateral side of the hinge assembly comprising a lock member on a second end of the latch pin engaging a lock recess on the second lateral side, the lock member operable to maintain the buttstock in the offset position when the lock member engages the lock recess; and a latch spring biasing the latch member in an inward direction and the lock member in an outward direction with respect to the hinge assembly; wherein rotating the latch member in opposing directions selectively engages the lock member with or disengages the lock member from the lock recess when the buttstock is in the offset position. a receiver; a barrel coupled to a front end of the receiver, the barrel defining a longitudinal axis and an axially extending bore forming a projectile pathway; an elongated buttstock defining a stock axis; a hinge assembly pivotably coupling the buttstock to the receiver, the hinge assembly comprising a fixed front hinge element coupled to the receiver, a movable rear hinge element coupled to the buttstock, and a hinge with hinge pin pivotably coupling the front and rear hinge elements together; the buttstock pivotably movable between an inline position, and an offset position in which the stock axis is laterally offset from the longitudinal axis; a latch pin rotatably and slideably carried transversely by the hinge assembly; a latching mechanism on a first lateral side of the hinge assembly comprising a latch member on a first end of the latch pin engageable with a latch recess on the first lateral side, the latching mechanism operable to maintain the buttstock in the inline position when the latch member engages the latch recess; a locking mechanism on a second lateral side of the hinge assembly comprising a lock member on a second end of the latch pin engaging a lock recess on the second lateral side, the lock member operable to maintain the buttstock in the offset position when the lock member engages the lock recess; and a latch spring biasing the latch member in an inward direction and the lock member in an outward direction with respect to the hinge assembly; wherein rotating the latch member in opposing directions selectively engages the lock member with or disengages the lock member from the lock recess when the buttstock is in the offset position.