The basis of this collection is formed by around 700 paintings, drawings and prints by Robert Lillie (1867-1949), which he bequethed to Milngavie Burgh Council. The works mainly cover landscape subjects, including scenes around Milngavie. Portraits and still life are represented in much smaller numbers.

Since 1961, Robert Lillie's founding bequest has been developed to form a collection of Scottish art dating from the late 19th century to the present day. There are around 450 works not by Lillie, covering a range of media, including paintings, drawings, prints, mixed media, sculpture, ceramics, glass and textiles.

Artists represented include several of the Glasgow Boys and all four of the Scottish Colourists. There is also a small group of historic ceramics, which includes Allander pottery, produced in Milngavie by Hugh Allan (1862-1909) from 1904-8. The gallery also holds a small collection of domestic pottery decorated by Bearsden born artist Jessie Marion King.