| John J. Cavanaugh III | |
| State: | Nebraska |
| District: | 2nd |
| Predecessor: | John Y. McCollister |
| Successor: | Hal Daub |
| State Legislature1: | Nebraska |
| District1: | 9th |
| Term Start1: | January 2, 1973 |
| Term End1: | January 5, 1977 |
| Predecessor1: | Sam Klaver |
| Successor1: | William E. Brennan |
| Birth Name: | John Joseph Cavanaugh III |
| Birth Date: | 1 August 1945 |
| Birth Place: | Omaha, Nebraska, U.S. |
| Party: | Democratic |
| Term Start: | January 3, 1977 |
| Term End: | January 3, 1981 |
| Education: | Regis University (BA) Creighton University (JD) |
| Allegiance: |  United States |
| Branch: | United States Army |
| Serviceyears: | 1968-1970 |
| Children: | 8, including John and Machaela |
John Joseph Cavanaugh III (born August 1, 1945) is an American politician and lawyer from Nebraska.
Born in Omaha, Nebraska, he graduated from Creighton Preparatory School in 1963, from Regis College in Denver, Colorado in 1967 and from Creighton University School of Law in 1972,. He was admitted to the bar in 1972 and set up practice in Omaha.
From 1968 to 1970 he served in the United States Army. In 1972 he was elected to the Nebraska Legislature and served until 1976 when he was elected to represent Nebraska's 2nd district in the Ninety-fifth United States Congress. He was reelected to the Ninety-sixth United States Congress serving from January 3, 1977, to January 3, 1981. He did not run for reelection in 1980, opting to resume his law practice in Omaha. He is a Catholic and was a delegate for Nebraska to the Democratic National Convention of 1980, 2000, and 2004. Cavanaugh is a member of the ReFormers Caucus of Issue One.[1]