An electronic device enclosure includes a side plate and a strengthening plate. The side plate includes a main body, a first mounting flange extending from a first edge of the main body, and a second mounting flange extending from a second edge of the main body. The first mounting flange defines a first clipping hole, and the second mounting flange defines a second clipping hole. The strengthening plate includes a first securing flange and a second securing flange. The first securing flange includes a first clamping portion. The second securing flange includes a second clamping portion. The strengthening plate is moveable in a first direction that is substantially perpendicular to the main body, to engage the first clamping in the first clipping hole; and the strengthening plate is rotatable about an axis, to engage the second clamping portion in the second clipping hole.