The Eustace Families Association was formed in 1976 by the late Donald W. Eustace of Chiswick (London), and other family members with the intentions of:

• Preserving for posterity the considerable knowledge now held in the histories of families originating in Flanders, Normandy and the British Isles who bear the name "Eustace" or spelling variants thereof and of their descendants throughout the world.

• Encouraging and assisting namesakes to research the story of their immediate family and to disseminate the knowledge gained to those interested.

• Developing and extending friendship and understanding between namesakes and welcoming visitors from overseas.

• Organizing family events and gatherings such as musters, tours and reunions.

• Membership is open to all bearers of the surnames Eustace, Eustice, Eustis, Eustance, Eustache and other variants as well as to descendents of these families.