An adjustable trigger mechanism assembly for a crossbow includes a trigger housing, a sear lever, a latch, trigger lever, and a linkage arm. The sear lever is pivotally engaged with the trigger housing and controls the movement of the latch. One end of the linkage arm is pivotally engaged with the sear lever. The trigger lever is pivotally engaged with the trigger housing. The trigger lever includes at least two moment arm holes for pivotally engaging an opposing end of the linkage arm. In an alternative embodiment, the at least two moment arm holes are formed in the sear lever. The at least two moment arms cause the trigger lever to have at least two different pull distances and pull forces.