The $101.3 million haul is just shy of the campaigns June fundraising, which reached $106.1 million.
Both numbers include money raised by Romney's campaign, the Republican National Committee, and several state parties in a joint committee known as Romney Victory.
If President Barack Obama raised less than Romney in July, it would mark the third consecutive month he has been outraised by his Republican challenger.
Obama's similar alliance of committees raised $71 million in June, the last numbers available. Campaign finance reports for July are not due until later in the month.
Romney's campaign said nearly 95% of donations -- some 600,627 -- received in July were for $250 or less.
In July, Romney's fundraisers included one held in Jerusalem and attended by major GOP donor Sheldon Adelson.
In announcing the numbers, Romney Victory National Finance Chairman Spencer Zwick said, "We are honored to have the support of a broad spectrum of donors -- independents, Democrats and Republicans -- whose support of Governor Romney shows that he has the needed plan to jumpstart our economy and get the country on the right track again.
"We are well on track to raise the money to be successful in November," he continued.
Zwick and a couple members of his finance team joined Romney on the road last week, attending closed finance events in Reno, Nevada, as well as one in Sun Valley, Idaho where Romney picked up Clint Eastwood's endorsement. The fundraisers, having occurred in the first week of August, did not factor into July's numbers.
In Sun Valley, Romney's young finance chair spoke briefly about how the campaign has outraised the competition and has more cash on hand than the Obama team.
"I want you to know we're using this money very wisely," Zwick said before urging donors to help them "turn this campaign into a cause" by reaching out to their friends and colleagues across the country.