What the Bleep Do We Know!? (stylized as What tнē #$*! D̄ө ωΣ (k)πow!? and What the #$*! Do We Know!?) is a 2004 American pseudo-scientific film that posits a spiritual connection between quantum physics and consciousness (as part of a belief system known as quantum mysticism). The plot follows the fictional story of a photographer, using documentary-style interviews and computer-animated graphics, as she encounters emotional and existential obstacles in her life and begins to consider the idea that individual and group consciousness can influence the material world. Her experiences are offered by the creators to illustrate the film's scientifically unsupported ideas.

Bleep was conceived and its production funded by William Arntz, who serves as co-director along with Betsy Chasse and Mark Vicente; all three were students of Ramtha's School of Enlightenment. A moderately low-budget independent film, it was promoted using viral marketing methods and opened in art-house theaters in the western United States, winning several independent film awards before being picked up by a major distributor and eventually grossing over $10 million. The 2004 theatrical release was succeeded by a substantially changed, extended home media version in 2006.

The film has been described as an example of quantum mysticism, and has been criticized for both misrepresenting science and containing pseudoscience. While many of its interviewees and subjects are professional scientists in the fields of physics, chemistry, and biology, one of them has noted that the film quotes him out of context.