Dummer made several charitable bequests in his will.
 He gave £200 to Harvard College, as well as a £50 grant for the purchase of books, and partially endowed two professorial chairs.
 His single largest gift was the grant of his Newbury property for a preparatory school.
 First called the Dummer Charity School, it opened on February 27, 1763.
 In its later history it was known as Dummer Academy, and until recently, Governor Dummer Academy.
In July 2006 it changed to The Governor's Academy (the benefactor's surname sounded uncomfortably like "dumber," it was decided, and thus elicited predictable taunts during sport meets).
Dummer's Georgian mansion remains a central feature of the school campus, now serving as the headmaster's residence.

The towns of Dummer, New Hampshire and Dummerston, Vermont were also named in his honor.
Dummer made several charitable bequests in his will.  He gave £200 to Harvard College, as well as a £50 grant for the purchase of books, and partially endowed two professorial chairs.  His single largest gift was the grant of his Newbury property for a preparatory school.  First called the Dummer Charity School, it opened on February 27, 1763.  In its later history it was known as Dummer Academy, and until recently, Governor Dummer Academy. In July 2006 it changed to The Governor's Academy (the benefactor's surname sounded uncomfortably like "dumber," it was decided, and thus elicited predictable taunts during sport meets). Dummer's Georgian mansion remains a central feature of the school campus, now serving as the headmaster's residence.
The towns of Dummer, New Hampshire and Dummerston, Vermont were also named in his honor.
William Dummer