Diplomatic relations between Germany and Romania began on 20 February 1880, when, following the Congress of Berlin, the German Empire recognized the independence of the Romanian United Principalities.

Romania opened official diplomatic relations with Germany and many other countries in 1880, but ties go back to before German Unification.

Romania in World War II supplied petroleum, equipment, and more troops to the invasion than any other Axis power.

Before the month was out, Germany had agreed to systematically supply the Romanian Army with German military vehicles, via the Olivenbaum I-III and Quittenbaum I programs.

The 75 mm Reșița gun (production started at the end of 1943) used the projectile chamber of the German Pak 40.

German-led Army Group South Ukraine could not take major operational decisions without securing Ion Antonescu's approval, even as late as 22 August 1944 (the day before he was dismissed).

Following Russia's invasion of Ukraine in 2022, Germany started deploying four Eurofighter jets to Romania to support the air policing mission, hosted at a military base near Constanta.