The 2012 Republican primary/caucus schedule below is based on the most current information available from state election boards. (President Obama’s nomination by the Democratic Party is not contested.)
For those states holding primaries, voters go to polling places and cast their ballots. In caucus states, voters gather in meeting places throughout the state to discuss candidates and reach a consensus on which candidate they will support.
| DATE | STATE | OUTCOME (top three finishers) |
| January 3 | Iowa (caucus) | Rick Santorum, 25 percent |
| January 10 | New Hampshire (primary) | Mitt Romney, 39 percent |
| January 21 | South Carolina (primary) | Newt Gingrich, 40 percent |
| January 31 | Florida (primary) | Mitt Romney, 46 percent |
| February 4 | Nevada (caucus) | Mitt Romney, 59 percent |
| February 4-11 | Maine (caucus) | Mitt Romney, 39 percent |
| February 7 | Colorado (caucus) | Rick Santorum, 40 percent |
| February 7 | Minnesota (caucus) | Rick Santorum, 45 percent |
| February 7 | Missouri* (primary) | Rick Santorum, 55 percent |
| February 28 | Arizona (primary) | Mitt Romney, 47 percent |
| February 28 | Michigan (primary) | Mitt Romney, 41 percent |
| March 3 | Washington (caucus) | Mitt Romney, 38 percent |
| March 6 | Alaska (caucus) | Mitt Romney, 33 percent |
| March 6 | Georgia (primary) | Newt Gingrich, 47 percent |
| March 6 | Idaho (caucus) | Mitt Romney, 62 percent |
| March 6 | Massachusetts (primary) | Mitt Romney, 72 percent |
| March 6 | North Dakota (caucus) | Rick Santorum, 40 percent |
| March 6 | Ohio (primary) | Mitt Romney, 38 percent |
| March 6 | Oklahoma (primary) | Rick Santorum, 34 percent |
| March 6 | Tennessee (primary) | Rick Santorum, 37 percent |
| March 6 | Vermont (primary) | Mitt Romney, 40 percent |
| March 6 | Virginia (primary) | Mitt Romney, 59 percent |
| March 6–10 | Wyoming (caucus) | Mitt Romney, 44 percent |
| March 10 | Guam (caucus) | Mitt Romney, 100 percent |
| March 10 | Kansas (caucus) | Rick Santorum, 51 percent |
| March 10 | Northern Mariana Islands (caucus) | Mitt Romney, 87 percent |
| March 10 | U.S. Virgin Islands (caucus) | Ron Paul, 29 percent |
| March 13 | Alabama (primary) | Rick Santorum, 35 percent |
| March 13 | Hawaii (caucus) | Mitt Romney, 45 percent |
| March 13 | Mississippi (primary) | Rick Santorum, 33 percent |
| March 20 | Illinois (primary) | Mitt Romney, 47 percent |
| March 24 | Louisiana (primary) | Rick Santorum, 49 percent |
| April 3 | District of Columbia (primary) | Mitt Romney, 70 percent |
| April 3 | Maryland (primary) | Mitt Romney, 49 percent |
| April 3 | Wisconsin (primary) | Mitt Romney, 43 percent |
| April 24 | Connecticut (primary) | Mitt Romney, 67 percent |
| April 24 | Delaware (primary) | Mitt Romney, 56 percent |
| April 24 | New York (primary) | Mitt Romney, 63 percent |
| April 24 | Pennsylvania (primary) | Mitt Romney, 58 percent |
| April 24 | Rhode Island (primary) | Mitt Romney, 63 percent |
| May 8 | Indiana (primary) | Mitt Romney, 65 percent |
| May 8 | North Carolina (primary) | Mitt Romney, 66 percent |
| May 8 | West Virginia (primary) | Mitt Romney, 70 percent |
| May 15 | Nebraska (primary) | Mitt Romney, 71 percent |
| May 15 | Oregon (primary) | Mitt Romney, 72 percent |
| May 22 | Arkansas (primary) | |
| May 29 | Texas (primary) | |
| June 5 | California (primary) | |
| June 26 | Utah (primary) |
* Missouri held a nonbinding primary on February 7 that did not select delegates to the 2012 Republican National Convention. Instead, the Missouri Republican Party held a caucus on March 17 to select convention delegates, and who the delegates choose will be announced after events in May and June.