Musa-juku (武佐宿) was the sixty-sixth of the sixty-nine stations of the Nakasendō highway connecting Edo with Kyoto in Edo period Japan. It was located in the present-day city of Ōmihachiman, Shiga Prefecture, Japan. Other kanji used to write "Musa" included 牟佐 and 身狭, but 武佐 became the official kanji in the Edo period.

The 69 Stations of the Nakasendō are the rest areas along the Nakasendō, which ran from Nihonbashi in Edo to Sanjō Ōhashi in Kyoto. The route stretched approximately 534 km (332 mi) and was an alternate trade route to the Tōkaidō.