A handle adjustment assembly of a walk-behind lawn mower for selectively adjusting an orientation of a handle of said mower, said mower having a deck, a plurality of ground engaging members connected to said deck, and a power supply connected to said deck for driving a cutting system, said handle adjustment assembly comprising: a pair of indexing mechanisms, wherein each of said indexing mechanisms comprises: a first indexing member attached to said deck or to a support member connected to said deck, said first indexing member having a plurality of annularly positioned first teeth, and a first indexing gap located within said plurality of first teeth of said first indexing member; a seconding indexing member selectively engageable with said first indexing member, said second indexing member having a plurality of annularly positioned second teeth,; and a clasp assembly connected to said first and second indexing members (32, 34), wherein said clasp assembly is actuatable between a locked position and an unlocked position; and a handle having a pair of opposing legs connected by a cross-bar, each of said legs having an end, and each end being attached to one of said indexing members (32, 34) of said adjustable handle assembly; wherein said clasp assembly of each indexing mechanism is actuatable between a locked position in which said second indexing member is engaged with said first indexing member wherein said first teeth being in meshing engagement with said second teeth and an unlocked position in which said second indexing member is disengaged from said first indexing member; wherein said second indexing member is rotatable relative to said first indexing member, and said height of said handle relative to said ground is adjusted in response to said first indexing members being rotatably adjusted relative to said second indexing members to provide a plurality of operative positions of said handle; characterized in that, in each of said indexing mechanisms: the second indexing member further comprises a first indexing lug located within said plurality of second teeth of said second indexing member; in said locked position, said indexing lug is located within said first indexing gap and; said second indexing member is rotatable relative to said first indexing member to selectively adjust said indexing lug to one of a plurality of operative positions provided by said first indexing member. a pair of indexing mechanisms, wherein each of said indexing mechanisms comprises: a first indexing member attached to said deck or to a support member connected to said deck, said first indexing member having a plurality of annularly positioned first teeth, and a first indexing gap located within said plurality of first teeth of said first indexing member; a seconding indexing member selectively engageable with said first indexing member, said second indexing member having a plurality of annularly positioned second teeth,; and a clasp assembly connected to said first and second indexing members (32, 34), wherein said clasp assembly is actuatable between a locked position and an unlocked position; and a first indexing member attached to said deck or to a support member connected to said deck, said first indexing member having a plurality of annularly positioned first teeth, and a first indexing gap located within said plurality of first teeth of said first indexing member; a seconding indexing member selectively engageable with said first indexing member, said second indexing member having a plurality of annularly positioned second teeth,; and a clasp assembly connected to said first and second indexing members (32, 34), wherein said clasp assembly is actuatable between a locked position and an unlocked position; and a handle having a pair of opposing legs connected by a cross-bar, each of said legs having an end, and each end being attached to one of said indexing members (32, 34) of said adjustable handle assembly; wherein said clasp assembly of each indexing mechanism is actuatable between a locked position in which said second indexing member is engaged with said first indexing member wherein said first teeth being in meshing engagement with said second teeth and an unlocked position in which said second indexing member is disengaged from said first indexing member; wherein said second indexing member is rotatable relative to said first indexing member, and said height of said handle relative to said ground is adjusted in response to said first indexing members being rotatably adjusted relative to said second indexing members to provide a plurality of operative positions of said handle; characterized in that, in each of said indexing mechanisms: the second indexing member further comprises a first indexing lug located within said plurality of second teeth of said second indexing member; in said locked position, said indexing lug is located within said first indexing gap and; said second indexing member is rotatable relative to said first indexing member to selectively adjust said indexing lug to one of a plurality of operative positions provided by said first indexing member. the second indexing member further comprises a first indexing lug located within said plurality of second teeth of said second indexing member; in said locked position, said indexing lug is located within said first indexing gap and; said second indexing member is rotatable relative to said first indexing member to selectively adjust said indexing lug to one of a plurality of operative positions provided by said first indexing member.