An adjustable mechanism for an archery sight is characterized by a unique elevation and tension adjustment assemblies which allow a user to quickly and easily set the sight for optimum performance. The mechanism includes an elevation base having an elevation rail and carriage assembly connected therewith for sliding movement along the base in a first direction. A windage carriage is connected with the elevation carriage for movement in a second direction, and a sight is connected with the windage carriage. A tension assembly including a unique traction wheel, yoke and cam mechanism is provided for adjusting the tension between the rail and the base, and an adjustable detent assembly is provided to stop movement of the elevation rail and carriage in selected elevation locations relative to the base.