This article is about the freeway in South Australia. For the freeway in Melbourne, also known as the South Eastern Freeway, see Monash Freeway.

The South Eastern Freeway (previously signposted as Princes Highway) is a 76 kilometre  controlled-access highway in South Australia. It carries traffic over the Adelaide Hills between Adelaide and the River Murray, near Murray Bridge, connecting via the Swanport Bridge to the Dukes Highway which is the main road route to Victoria. It is often referred to by South Australians simply as the Freeway, as it was the first freeway in South Australia, and is still the longest, and the only one with "Freeway" in its name rather than "Expressway" or "Highway". It is a part of the National Highway network linking the state capital cities Adelaide to Melbourne and signed as National Highway M1. The South Eastern Freeway includes 500-metre-long twin-tube tunnels (the Heysen Tunnels) in the descent towards Adelaide, the first of their kind on the National Highway. It is designated as the M1.

South-Eastern Freeway may refer to:

• South Eastern Freeway, running southeast from Adelaide in South Australia, Australia
• Monash Freeway, running southeast from Melbourne in Victoria, Australia