| Country: | DEU |
| Type: | B |
| Route: | 73 |
| Map: | B073 Verlauf.svg |
| Length Km: | 100 |
| Direction A: | Northwest |
| Terminus A: | Cuxhaven |
| Direction B: | Southeast |
| Terminus B: | Hamburg |
| States: | Lower Saxony, Hamburg |
The Bundesstraße 73 or B73 is a German federal highway running in a northwesterly to southeasterly direction from Cuxhaven to Hamburg. It runs partially beside the Bundesautobahn 26.