Island Line is the smallest of the Train Operating Companies that make up Britain's National Rail network. The franchise is currently operated by the Stagecoach Group. Island Line is the only passenger franchise that includes maintenance of the infrastructure in addition to the running of passenger services.

Island Line operates a single railway line on the Isle of Wight, running some 8½ miles from Ryde Pier Head to Shanklin down the eastern side of the island. The line was electrified using the third rail system in 1967. Trains connect with passenger ferries to Portsmouth Harbour at Ryde Pier Head, and these ferries in turn connect with the rest of the National Rail network. The line also connects to the Isle of Wight Steam Railway, a steam operated heritage railway at Smallbrook Junction.

Because of tight clearances within a tunnel at Ryde, standard National Rail vehicle types cannot operate on the Island Line. Currently, the services are operated using Class 483 units, which are refurbished ex-London Underground tube trains originally built in 1938. These replaced the older Class 485 and Class 486 units, which dated from 1923.

Island Line is reportedly Britain's most reliable and punctual train company. The shortness and simplicity of the route may be the reason for this.

The towns and villages served by the line are listed below.

• Ryde
• Smallbrook Junction
• Brading
• Sandown
• Lake
• Shanklin

In the mid-1990s it was planned to extend the line south to Ventnor. However, this now seems unlikely to happen, due in part to the high costs involved.