Bernhard Wachstein (31 January 1868 in Tluste, southeast Galicia – 15 January 1935 in Vienna) was a Jewish community historian and bibliographer who rebuilt, expanded, and modernized the library of the Israelitische Kultusgemeinde Wien (Vienna Israelite Community).

[1]: 155–156  He also performed important bibliographic work, particularly relating to the history of Austrian Jews.

After completing his Talmudic, philosophical, historical, and bibliographic studies, Bernhard Wachstein settled in Vienna and became a librarian for the Israelitische Kultusgemeinde Wien (Vienna Israelite Community).

He was involved with community history and genealogy, and he made important contributions in these areas.

He married Marie (née Weiss) and they had two children Max Wachstein (b.