The Monkey Peg is an obstacle, firstly introduced as the fifth on American Ninja Warrior 5 in Miami, and appeared again on American Ninja Warrior 6 in Venice Beach. It consisted of two sections. The first section was on an upward slant and has pegs placed (referred as the Monkey Bar section). The second section was a pegboard on a downward slant with holes in it (referred as the Pegboard section). There was a peg in each of the first two holes. After competitors traversed the first section, they must make a transition to the two loose pegs on the second section. Once there, they must move the two pegs from hole to hole, to reach the landing mat.
The second version of the Monkey Peg (called as the Monkey Pegs) appeared as the fourth obstacle on American Ninja Warrior 7 in San Pedro (Military). Unlike on the original Monkey Peg, this version was entirely made with the arc-shaped pegboard. There were a total of twelve pegs, with ten stationary pegs, in which competitors must traverse it in a similar fashion with the Monkey Bar section of the Monkey Peg, and two removable pegs, in which competitors must move them from hole to hole, in a similar fashion with the Pegboard section of the Monkey Peg.
Later, a modified version of this obstacle (called as the Swinging Peg Board) was used as the eighth obstacle on American Ninja Warrior 9 in Los Angeles and Celebrity Ninja Warrior (during Stephen Amell's run).