Birnbaum (German: "pear tree") may refer to:
- Birnbaum an der Warthe and Kreis Birnbaum, today Międzychód, a city and county in Posen district, Poland
- Birnbaum (Franconian Forest) , a city in the Franconian Forest
- Birnbaum (Gummersbach), a district of Gummersbach, North Rhine-Westphalia, Germany
- Birnbaum (Lesach), a city in Lesach
- Birnbaumer Wald, an elevated plain on the edge of the Alps in Slovenia
As a surname
Birnbaum is a German and Ashkenazi Jewish surname that can refer to:
- Alfred Birnbaum
- Allan Birnbaum
- Heinrich Birnbaum
- Jeremiah Birnbaum
- Karl Birnbaum (1878-1950), German neurologist
- Mark Birnbaum
- Menachem Birnbaum
- Nathan Birnbaum, Jewish philosopher
- Norman Birnbaum (born 1926), US sociologist
- Solomon Birnbaum, Yiddish linguist and son of Nathan Birnbaum
- Uriel Birnbaum
- Philip Birnbaum, translator of Jewish prayer book
- Yaakov (Jacob) Birnbaum, human rights activist
- George Burns (born Nathan Birnbaum)
