Philip Cary Plait, Ph.D. (aka "The Bad Astronomer") is a US astronomer, skeptic, writer and popular science blogger. He is a well known author and public figure in the fields of astronomy and science.

Plait gained his Ph.D. in astronomy from the University of Virginia in 1994. He began his career with the NASA Goddard Space Flight Center. His first foray into public life was with his blog that described "bad astronomy" in movies and in public perception in general. This led to Plait's first book Bad Astronomy: Misconceptions and Misuses Revealed, from Astrology to the Moon Landing "Hoax" (2002). In 2008, he became President of the James Randi Educational Foundation, serving in that position until January 1, 2010.

Dr Phil Plait remains a popular and well known figure popularising science and astronomy.