An adjustable hanger bar assembly securable to a support structure including an elongate first member and an elongate second member. The first member is telescopically received within the second member. A securement section is supported on the second member. The securement member captures the first member within the second member and permits relative movement between the first and second members in a direction along a longitudinal axis of the first and second members, and restricts motion between the first and second members in a direction transverse to the longitudinal axis.