The Tempoku Line (天北線, Tempoku-sen) was a railway line most recently operated by Hokkaido Railway Company (JR Hokkaido) in Hokkaidō, Japan.

The 148.9 kilometres line connected from Otoineppu to Minami-Wakkanai via Nakatonbetsu, Hamatonbetsu and Sarufutsu until its closure in 1989.

All section was opened in 1922, as the first railway line for Wakkanai.

In 1987, JNR was privatized, and this line was inherited by JR Hokkaido, but abandoned on 1 May 1989.

Soya Bus (Belong to Tokyu Group until 1999) have altered the Tenpoku Line since 1989.