Abstract: A height adjustable light fixture support includes a first U-shaped bracket with a crosspiece and first and second depending legs. The U-shaped bracket will be secured in a ceiling box. A slidable, height adjustable second U-shaped bracket supports a light and includes separated first and second plates, each of which is shaped to define a respective sliding channel in which one of the legs of the first bracket is slidably receivable. The plates are connected by a second crosspiece. Spring loaded members supported by each plate each include a spherical head which penetrates into the sliding channel of its plate to frictionally engage the respective leg of the first bracket in the channel. Temporary release of these members enables the height of the light fixture to be easily adjusted by moving the second bracket.