Wilhelm Heitmüller (3 August 1869 – 29 January 1926) was a German Protestant theologian, born in Döteberg, presently a division in the town of Seelze.
Following completion of theological studies, he attended the minister's seminary at Loccum.
In 1902 he received his habilitation at Göttingen, and in 1908 became a professor of New Testament studies at the University of Marburg.
Heitmüller was a prominent member of the Religionsgeschichtliche Schule (History of religions school).
Along with Wilhelm Bousset (1865–1920), he was editor of the journal Theologische Rundschau.