Rick Tyler, Newt Gingrich's spokesman, said that he, campaign manager Rob Johnson and senior strategists had all quit, along with aides in the early primary and caucus states of Iowa, New Hampshire and South Carolina.
In addition to Tyler, Johnson and Rials, aides who quit include senior adviser Sam Dawson, South Carolina director Katon Dawson, and New Hampshire director Dave Carney. The entire full-time staff in Iowa, six aides, also quit.
Gingrich's now-former spokesman cited differences over the direction of the campaign.
Gingrich, a former speaker of the House of Representatives, posted on his Facebook page: "I am committed to running the substantive, solutions-oriented campaign I set out to run earlier this spring. The campaign begins anew Sunday in Los Angeles."
The upheaval in the campaign was likely to lead to a shakeup in the race for the party's presidential nomination, as well, as rivals reach out for disaffected staff, and possibly for donors who have been aligned with the former Georgia congressman.
Gingrich has long been viewed, by even his closest allies, as a fountain of policy ideas but a man who is unable to avoid speaking in ways that spark unwelcome controversy.
Even before the sudden departures of his top aides, Gingrich's campaign was off to a notably rocky start. Within days of formally announcing he would run, he was assailed by conservatives for criticizing a plan to remake Medicare that Republicans pushed through the House.
While Gingrich told his now-departed aides he would remain in the race, he faces formidable obstacles in assembling a new team in time to compete in a campaign that's well under way. He has the allegiance of several former aides who served him when he was in Congress, but most if not all of them have moved into other fields.
Most immediately, he is scheduled to participate in a debate next Monday in New Hampshire.
Gingrich, 67, last served in public office more than a decade ago. He resigned as speaker of the House after two terms following an unexpectedly close mid-term election in 1998 in which Republicans gained far fewer seats than he had predicted.
In the years since, he has established a virtual one-man think tank, publishing books and speaking publicly.
Gingrich announced his presidential exploratory committee in May and is not required to report the results of his campaign fundraising until mid-July.
The Associated Press contributed to this report.