The Diana, Princess of Wales Memorial Fountain is a memorial to Diana, Princess of Wales. It was designed with children in mind. It is located in the southwest corner of Hyde Park in London, just south of the Serpentine Lake and east of the Serpentine Gallery. Its cornerstone was laid in September of 2003 and it opened on July 6, 2004.

The fountain was designed by Kathryn Gustafson, an American landscape artist, and cost 3.5 million pounds. The 545 individual pieces of Cornish granite were cut using sophisticated computer-guided cutting machines by S McConnell and Sons in Kilkeel, Northern Ireland.

Although described as an oval stone fountain, it has the form of a large, oval stream bed about 50 by 80 m (165 by 260 feet) that surrounds, and is surrounded by, a lush grassy field. The granite streambed is from 3 to 6 m (10 to 20 feet) wide and quite shallow and is laid out on a gently sloping portion of the park, so that water pumped to the top of the oval flows down either side. One side of the stream bed descends fairly smoothly to the downhill end of the oval with gentle ripples. The other side consists of a variety of steps, rills, curves, and other shapes so that the water plays in interesting ways as it flows to the tranquil pool at the bottom. The two sides were intended to show the two sides of Diana's life, both happy times and turmoil.

Detail of stream bed without water flowing

In addition, because Diana was a contemporary and accessible princess, the fountain's goal was to allow people access to the structure and to the water for quiet wading and contemplation. However, shortly after its opening and after three hospitalizations caused by people slipping in the water, the fountain was closed. It reopened in August 2004, surrounded by a new fence, and people are now prevented from walking or running in the water by six wardens.

However, even though the fountain was only open for a part of the 2004 season, and the weather was not particularly wet, the grass adjacent to part of the fountain was almost obliterated, and it appeared that it would turn to a quagmire if heavy rain ever fell during the main visiting season. Therefore in December 2004, another alteration project was started. This involved work on the drainage, together with laying new hard surfaces on some of the most frequently walked areas of the site and the planting of a special hard wearing rye grass mix in others.