The Finnish national road 45 (Finnish: Kantatie 45; Swedish: Stamväg 45) is the 2nd class main route between the major cities of Helsinki and Hyvinkää in southern Finland.

[1] It runs from Käpylä in Helsinki to the Hyrylä in Tuusula as a motorway called Tuusula Highway (Finnish: Tuusulanväylä, Swedish: Tusbyleden),[2] where it continues to border of the Hyvinkää town and the national road 3 as a smaller road called Hämeentie.

The road passes through the following localities: