Bo Stefan Alexander Olsdal is a Swedish-Luxembourgish musician, best known as the bassist/guitarist of the alternative rock band Placebo, he is also part of the electronic band Digital 21 + Stefan Olsdal and launched the electronic/dance remix at Hotel Persona.

Placebo is a British alternative rock band, formed in London in 1994 by vocalist–guitarist Brian Molko and bassist–guitarist Stefan Olsdal, and in late 1994 Robert Schultzberg joined as drummer. Molko was born in Belgium and Olsdal and Schultzberg in Sweden; Molko and Olsdal grew up in Luxembourg before separately relocating to London and becoming British citizens. Schultzberg left the band in 1996 shortly after the release of the band's eponymous debut album due to conflicts with Molko, and was replaced the same year by Steve Hewitt.