Bairdston is an unincorporated community in Sullivan County, Missouri, United States.
The community is at the intersection of Missouri routes BB and OO approximately six miles northwest of Milan.
A variant name was "Bairdstown". The community was platted in 1859 by Miles B. Baird, and named for him. A post office called Bairdstown was established in 1858, and remained in operation until 1903.