The museum garden is 17th-century-style knot garden, designed by the Dowager Marchioness of Salisbury, President of the Garden Museum. It was officially opened in 1983 by HM Queen Elizabeth, the Queen Mother.
The garden is set in the old graveyard surrounding the museum, which was formerly the parish church of St Mary-at-Lambeth. It features plants of the period and contains the tombs of the famous 17th-century gardeners and plant-hunters, the John Tradescants, father and son. There is a wild garden at the front of the museum, created in 2007.