The Finnish national road 13 (Finnish: Valtatie 13, Swedish: Riksväg 13) is a highway in Finland. The highway connects the communities of Kokkola and Lappeenranta via Jyväskylä. From Nuijamaa, which is now part of Lappeenranta, the road continues after the Russian border all the way to Vyborg.
In the 1938 numbering system, national road 13 ran from Vyborg (then Viipuri) to Kokkola via Mikkeli and Jyväskylä. It was one of three highways that fanned out from Vyborg. When Karelia was ceded to the Soviet Union after WWII, the route was cut off at Lappeenranta.
The road was built between the 1950s and 1980s to mainly follow the 1938 routing. The most significant differences are as follows:
Regional road 392 between Lauritsala and Nuijamaa in Lappeenranta was renumbered as a portion of national road 13 in the 1990s following the collapse of the Soviet Union, when national road 13 returned to being the main road leading to Vyborg.