The Ohmi Railway Main Line (近江鉄道本線 Ōmi Tetsudō hon-sen?) is a regional railway line in Shiga Prefecture operated by the private railway operator Ohmi Railway. It connects the cities of Maibara and Koka. Its alignment is parallel with the Tōkaidō Shinkansen between Takamiya and Gokasho.
The line is 47.7 kilometres (29.6 mi) long, extending from Maibara to Kibukawa. The line connects with the JR Central Tōkaidō Main Line and Tōkaidō Shinkansen, and the JR West Hokuriku Main Line and Biwako Line at Maibara, and the JR West Kusatsu Line and the Shigaraki Kōgen Railway Shigaraki Line at Kibukawa.
The Hikone to Yokaichi section opened in 1898, reaching Kibukawa in 1900. The Hikone to Takamiya section was electrified at 600 V DC in 1925, with the Takamiya to Kibukawa section electrified at 1,500 V DC in 1928, and the Hikone to Takamiya section raised to that voltage at the same time. The Hikone to Maibara section opened in 1931 following the construction of the 340 m Sawayama Tunnel, electrified from opening.
Transport of postal items ceased in 1984, and freight services ceased in 1988.