The Government National Mortgage Association (GNMA), or Ginnie Mae, is a government-owned corporation of the United States Federal Government within the Department of Housing and Urban Development (HUD). It was founded in 1968 and works to expand affordable housing by guaranteeing housing loans (mortgages) thereby lowering financing costs such as interest rates for those loans. It does that through guaranteeing to investors the on-time payment of mortgage-backed securities (MBS) even if homeowners default on the underlying mortgages and the homes are foreclosed upon.

Ginnie Mae guarantees only securities backed by single-family and multifamily loans insured by government agencies, including the Federal Housing Authority, Department of Veterans Affairs, the Department of Housing and Urban Development’s Office of Public and Indian Housing, and the Department of Agriculture’s Rural Development. Ginnie Mae neither originates nor purchases mortgage loans nor buys, sells or issues securities. The credit risk on the mortgage collateral underlying its mortgage-backed securities primarily resides with other insuring government agencies.

Ginnie Mae is similar to Fannie Mae (Federal National Mortgage Association) and Freddie Mac (Federal Home Loan Mortgage Corporation) with the difference being that Ginnie Mae is a wholly owned government corporation whereas Fannie Mae and Freddie Mac are "government-sponsored enterprises" (GSEs), which are federally chartered corporations privately owned by shareholders. Today, Ginnie Mae securities are the only mortgage-backed securities that are backed by the "full faith and credit" guaranty of the United States Federal Government, although some have argued that Fannie Mae and Freddie Mac securities are de facto or "effective" beneficiaries of this guarantee after the Federal Government rescued them from insolvency and placed them under government conservatorship in September 2008 during the Great Recession.