Dittmer is an unincorporated community in western Jefferson County, Missouri, United States. It is located about 14 miles northwest of Hillsboro on Route 30. This is shown on an early railroad map published in 1891 as "Dittmer's Store."
Dittmer was named for William Dittmer.
The settlement is home to the Vianney Renewal Center, a treatment center for Catholic clergy with sexual or other disorders.