In a statement, the institute said that its board of trustees had accepted Elliott’s resignation at its June board meeting.
Elliott, a former chief executive of the West Midlands Regional Assembly and director of the Government Office for the West Midlands, was appointed as the organisation’s chief executive in October 2010 and took up her appointment at the beginning of January 2011.
The statement said that Elliott would lead the RTPI until a successor is appointed and that the board expects to begin the search for a new chief executive "after the summer".
Chair of the board of trustees, Graham Stallwood, said: "It is with sadness that the board accepted Trudi Elliott’s resignation.
"Trudi is an outstanding and deeply committed leader of the RTPI. As most of you know, this commitment has required that she is based in London during the week.
"Trudi feels that the time has now come for her to return to living full-time in the West Midlands and to look to new challenges."