National Road 73 (Riksväg 73), Nynäsvägen, is a Swedish national road in Sweden between Stockholm and Nynäshamn.

National road 73 begins at the Johanneshov junction at Gullmarsplan in Stockholm with connections from the bridges Johanneshovsbron and Skanstullsbron and county road 226 (Huddingevägen), passing above Södra länken and continues southwards.

At Gubbängen junction goes beneath county road 229 (Örbyleden/Tyresövägen), continues past Farsta, passing the municipal border of Huddinge where then county road 271 (Magelungsvägen) joins.

In Handen it goes above the end point of county road 260 (Gudöbroleden), continues past Jordbro, Västerhaninge, Landfjärden and Ösmo to Nynäshamn, where national road 73 comes to an end at the railway station and the Gotland quay.

The road is a motorway between Stockholm and Västerhaninge.