A lighting junction box assembly includes a lighting junction box housing having a body with a partially cylindrical sidewall, a closed end, and a circular opening opposite the closed end, and flat inset facets with knock-out holes formed on the sidewall. A pair of bracket assemblies attaches the lighting junction box housing in a vertically adjustable position onto hanger bars fixed between ceiling joists. The adjustable vertical position provides for use and mounting in ceilings of various thicknesses. The bracket assemblies provide the ability to adjust the vertical position of the lighting junction box housing during installation by a simple fastener inside the junction box which may be tightened without the use of tools. This capability is accomplished by the use of a carriage bolt which may be vertically positioned in a slot in the bracket.