Abstract: An auxiliary mirror module for extending the viewing area of an existing side view mirror of the type mounted in a housing is disclosed. The module comprises a casing configured to slidably fit over at least a portion of the housing, the casing including a pair of opposed channel sections. The casing is supported on the housing by sliding the channel sections over opposed edges of the housing. The module includes an auxiliary mirror supported alongside and co-planar with the side view mirror. The casing further includes a threaded fastener for engaging a support bracket to retain the casing relative to the mirror. Retaining structure for securing the module to the housing support is also disclosed.