An adjustable frame connector comprising at least two fixed tubular legs and an adjustable tubular leg. The fixed legs have inner ends that are joined together, and have longitudinal axes that intersect each other at right angles. The adjustable leg has an inner end that is pivotally attached to the fixed legs at their juncture so that the adjustable leg can be moved from a first position wherein its longitudinal axis is coaxial with the longitudinal axis of a first one of the fixed tubular legs to a second position wherein its longitudinal axis is at a right angle to the longitudinal axis of the first one of the fixed tubular legs. Releasable locking means allows the adjustable leg to be releasably locked into position relative to the first one of the fixed tubular legs at any selected location along the ninety degree arc between its first and second positions.