National road 8 (Polish: Droga krajowa nr 8, abbreviated as DK8) is a route in the Polish national road network, running diagonally through Poland from the Czech border in Kudowa Zdrój in the south-west to Raczki near the border with Lithuania in the north-east, through the Lower Silesia, Greater Poland, Łódź, Masovian and Podlaskie voivodeships.

For most of its length it forms the Polish section of the European route E67 known as the Via Baltica between Warsaw and Tallinn.

Until 2022 it was the longest road in Poland with a total length of 804 km.

In December 2022 the last segment of the DK 8 to Budzisko on the border with Lithuania was made part of the DK 61.

The middle section of the route, from the A8 motorway to Białystok, has the status of an expressway marked as S8.