A real estate investment trust or REIT ( /ˈriːt/) is a tax designation for a corporate entity investing in real estate. The purpose of this designation is to reduce or eliminate corporate tax. In return, REITs are required to distribute 90% of their taxable income into the hands of investors. The REIT structure was designed to provide a real estate investment structure similar to the structure mutual funds provide for investment in stocks.

REITs can be publicly or privately held. Public REITs may be listed on public stock exchanges.

REITs can be classified as equity, mortgage, or a hybrid.

The key statistics to examine in a REIT are net asset value (NAV), funds from operations (FFO), adjusted funds from operations (AFFO) and cash available for distribution (CAD). In the period from 2008 to this writing (2011), REITs face challenges from both a slowing United States economy and the late-2000s financial crisis, which depressed share values by 40 to 70 percent in some cases.

Real estate investment trusts originated in the 1880s at a time when investors could avoid double taxation, or a tax at corporate and individual level. In the 1930s, this tax benefit was removed, causing investors to pay "double tax." President Eisenhower signed the REIT tax provision contained in the Cigar Tax Excise Tax Extension in 1960.