Allan has been chief executive of rival developer St Modwen Properties for the last three years after joining from the Unite Group which he ran for 10 years.
Allan, a qualified chartered accountant and a member of the Royal Institution of Chartered Surveyors, will take up the new role next year on a date to be confirmed.
Cressida Hogg, chairman of Landsec, said: “I am delighted to announce that Mark is to join Landsec as our next CEO.
“Mark has been a highly successful CEO of two companies in the property sector.
“He has demonstrated strong management skills and the strategic insights that we believe will build on the strengths of our business today and be invaluable for the next phase of Landsec’s evolution.”
Allan said: “Landsec is an iconic property company with a fantastic heritage and I am delighted to have the opportunity to lead it. The world of real estate is undergoing significant change and I am confident, with the skills and experience already in place, that great opportunities lie ahead. I am looking forward to working with everyone at Landsec, the board and its partners and customers.”
Robert Noel will continue as CEO until a further announcement about Allan’s joining date.