Extra Space Storage (NYSE: EXR) is a US provider of self-storage units, with over 1,415 facilities across 38 states plus Washington, D.C. and Puerto Rico. Headquartered in Cottonwood Heights, Utah, Extra Space Storage is the second largest owner and/or operator of self-storage properties in the United States, as well as the largest self-storage management company.

Extra Space Storage has been a publicly traded real estate investment trust (REIT) since 2004, and is traded on the New York Stock Exchange with the ticker symbol EXR. The company was founded in 1977 by Kenneth Woolley, who remains the chairman. Since Apr 2009, Spencer Kirk has served as the company's CEO.

Extra Space Storage, the publicly traded REIT launched on the NYSE under the symbol "EXR" in August 2004 is the successor to Extra Space Development Co., a Limited Partnership which was founded in 1979 by Kenneth M.Woolley as General Partner, Neilson Enterprises as Limited Partner, and with Richard S. Tanner joining Woolley as an additional General Partner shortly after its creation. Prior to creating Extra Space Development Woolley and Tanner had worked together in another real estate venture in 1975,and Woolley had built his first self-storage facility in Billings, Montana in 1977 with Bill Nielson of Nielson Enterprises. Between 1979 and 2004, Woolley and Tanner developed self-storage properties in California, Utah, Florida, Massachusetts, New Hampshire, Illinois, Nevada, Rhode Island, New York, Connecticut, and New Jersey. Tanner served as President of the affiliated Extra Space Management Co. for 15 years which managed owned and third party self-storage properties. Both Woolley and Tanner served as licensed Real Estate Brokers in multiple states which facilitated third party management and several acquisitions of existing storage properties. Over the years, several of the self-storage properties developed by Extra Space Development were sold to Public Storage or Storage USA, and Storage USA was acquired by Extra Space Storage shortly after going public.

Before going public, Extra Space Development created several joint ventures partnerships including with Prudential Real Estate and in 1998, eventual CEO Spencer Kirk joined Woolley as a 50-50 partner for many new properties being developed or acquired. . Kirk was previously the co-founder of Megahertz, a laptop modem company that was purchased by USRobotics in 1994, and later by 3Com.

In August, 2004, Extra Space held its initial public offering on the New York Stock Exchange using the symbol "EXR", opening at $12.50 per share.

In 2005, as part of a joint venture with Prudential Real Estate, Extra Space acquired Storage USA for $2.3 Billion, adding 458 additional properties. With Woolley as CEO and Tanner as its SVP of Construction and Development, Extra Space Storage continued growth through developments exceeding $100M/yr, combined with additional acquisitions of existing properties and expansion of its 3rd party management contracts. With the economic changes of 2008 that especially impacted commercial real estate financing and construction, development and construction was wound down by 2010 and Extra Space focused growth efforts on selective acquisitions and third party management of properties under the Extra Space Storage brand.

As of August, 2014, Extra Space Storage owns and operates 1,106 facilities in the US. The company's properties comprise approximately 740,000 units, and over 81 million square feet of rentable storage space. Various types of storage units are offered by the company, including RV, boat, and automobile storage. The company also offers climate-controlled units, indoor and outdoor units, and locker units.