War bonds are debt securities issued by a government to finance military operations and other expenditure in times of war without raising taxes to an unpopular level. They are also a means to control inflation by removing money from circulation in a stimulated wartime economy. War bonds are either retail bonds marketed directly to the public or wholesale bonds traded on a stock market. Exhortations to buy war bonds have often been accompanied by appeals to patriotism and conscience. Retail war bonds, like other retail bonds, tend to have a yield which is below that offered by the market and are often made available in a wide range of denominations to make them affordable for all citizens.

Series E United States Savings Bonds were government bonds marketed by the United States Department of the Treasury as war bonds during World War II from 1941 to 1945. After the war, they continued to be offered as retail investments until 1980, when they were replaced by other savings bonds.