Abstract: A fastening device includes a clip 14 with a first clip member 22 and a second clip member 24. The second clip member 24 is resiliently pivotable relative to the first clip member 24, such that a flat object may be resiliently clamped between the first and second clip members 22, 24. The clip 14 comprises a strap holding portion 30, where a first end of a flexible strap 16 is held within the strap holding portion 30. The clip 14 further comprises a strap receiving portion 32 arranged at a distance from the strap holding portion 30. The strap receiving portion is shaped to receive a portion of the strap. By use of the fastening device, an element, and in particular a lighting device 12, may be alternatively fixed to another element by the flexible strap 16 or may engage a flat object within the clip 14.