A guide is presented intended for use in a sunshade assembly of the type comprising a flexible sunscreen having opposed longitudinal edges and two opposed longitudinal guides each comprising at least two spaced guide legs for defining there between a guide channel for receiving therein and guiding corresponding ones of the opposed longitudinal edges of the sunscreen. The guides and longitudinal edges are provided with cooperating guide locking members and edge locking members for preventing the longitudinal edges of the sunscreen from moving out of the guide channels. The guide locking members are defined on separate parts engaging the guides.