Johnstone (Scots: Johnstoun, Scottish Gaelic: Baile Iain) is a town in the administrative area of Renfrewshire and larger historic county of the same name, in the west central Lowlands of Scotland.

The town lies 3 miles (5 km) west of neighbouring Paisley, 12 miles (19 km) west of the centre of the city of Glasgow and 12 miles (19 km) north east of Kilwinning. Part of the biggest conurbation in Scotland, Johnstone is at the western edge of the Greater Glasgow Urban Area.

Johnstone was largely a planned community which grew up around the house of Easter Cochrane, later known as Johnstone Castle, seat of the Houston or Houstoun family who gained their name from the nearby village of Houston. In 1782, the Laird, George Houstoun, commissioned designs for a series of regular residential streets, which now form the town centre. At this early stage of development, the town's population including the local estate and rural hinterland was around 1,500. Two mirroring civic squares were also constructed in the town: Houstoun Square and Ludovic Square, the latter named for the Laird's son, and by 1794 the town had gained its current parish church. Johnstone was raised to the status of a police burgh with significant local powers, a status which is now defunct. The former court building continues to stand in Collier Street.

Industrial development brought both prosperity and poverty to the community. Coal mining occurred in Johnstone, although its main industry was related to the thread and cotton industries, with mills powered by the Black Cart Water which runs to the north of Johnstone. A six-storey cotton mill, one of the largest in Scotland, was built in 1782, and was rescued from failure by Robert Burns of Paisley sometime before 1812. Burns introduced Richard Arkwright's methods for spinning cotton. As the community expanded, slum conditions formed in part of the town: the population by 1831 had increased to a sizeable 5,600. Unfortunately, the owners of Johnstone mill did not make much philanthropic progress among their worker population, and the situation was not addressed until the 1930s by a significant expansion of the size of Johnstone to include a number of purpose-built residential estates.

Much of Johnstone's feudal heritage has disappeared. With the death of the last Laird in 1931, Johnstone Castle fell into disrepair before being largely demolished in 1950. The remaining tower was purchased in 2001 and is now a private residence. On the site of the former grounds now lies two housing estates, Johnstone Castle and Cochrane Castle. Embedded within Cochrane Castle is the Cochrane Castle Golf Club, which once held the world record for the longest hole.

More recently, Johnstone History Museum opened in 2008 – notably becoming the world's first museum located inside a supermarket.

In 2015, the new Town Hall was completed at a cost of £14.5m.

The town is home to Johnstone Pipe Band who compete in the highest level of pipe band competitions, Grade 1. The band was founded in 1943 and wears the Blue Mackay tartan.