Bronisław Knaster (22 May 1893 in Warsaw - 3 November 1990 in Wrocław) was a Polish mathematician; from 1939 university professor in Lwów, from 1945 in Wrocław.
Knaster received his Ph.D. degree from Université de Paris in 1925, under the supervision of Stefan Mazurkiewicz. These two individuals are considered by many among the greatest point-set topologists of all time.
He worked in topology and set theory. He is perhaps best known for his discovery of the pseudo-arc, the first example of a hereditarily indecomposable continuum, and the Knaster continuum, or buckethandle continuum.
In 1963 he received a Nagroda państwowa (national award) and a degree. He was famous for his sense of humour. He organized meetings of mathematicians called knasteria after the history of this discipline in Poland.