The former technology executive announced on Twitter that she is suspending her campaign.
The 61-year-old drew positive reviews for several strong debate performances, in which she promoted her business expertise and argued that as the lone woman in the GOP field she was best positioned to oppose likely Democratic nominee Hillary Clinton. But she struggled to build support in a crowded primary field and her poll numbers lagged.
Fiorina announced her candidacy in April. She previously ran unsuccessfully for Senate in California.
Fiorina struggled with criticism of her time at Hewlett-Packard, where she was ousted from the top job in 2005, after leading a major merger and laying off 30,000 people.
New Jersey Gov. Chris Christie is expected to also drop out of the 2016 race for the White House after finishing sixth in the New Hampshire primary. That’s according to a two people familiar with his plans.