FedEx Ground Package System, Inc., also known simply as FedEx Ground, is an American ground package delivery company headquartered in Moon Township, Pennsylvania, a suburb of Pittsburgh. It is a subsidiary of the FedEx Corporation. The company began as Roadway Package System (RPS), founded in 1985 by transportation company Roadway Services Inc., later renamed Caliber System. FedEx bought Caliber in 1998 to complement its existing FedEx Express business and rebranded Caliber's RPS package delivery service FedEx Ground in 2000.

FedEx Ground provides US and Canada domestic services as well as international services between the two, branded FedEx International Ground. Its services are cheaper than the time-definite services offered by FedEx Express and its drivers are primarily owner/operators, independent contractors who control individual delivery routes and territories. In addition to its core commercial package services, the company's services include FedEx Home Delivery, a US residential delivery service, and FedEx Ground Economy (formerly FedEx SmartPost), a low-cost parcel consolidation service.

When RPS was founded on March 11, 1985, it intended to out-compete UPS Ground by focusing on efficiency and structuring itself for lower costs. One result of this drive for efficiency was RPS' use of barcodes on packages allowing it to track and sort shipments much more effectively. After an intensive effort to shift its operations to use the new technology, RPS became the first company able to track a package through the delivery cycle.

Its parent company, RSI, already owned a number of transportation companies including national less than truckload (LTL) carrier Roadway Express. This backing allowed RPS to grow quickly and by 1988 it was operating 130 terminals covering 70% of the US. After RSI spun off Roadway Express in 1995 and changed its name to Caliber System, RPS was its largest subsidiary.

In 1997, Fred Smith, founder of FedEx, contacted Dan Sullivan, co-founder of RPS and now president of Caliber System, about merging the two companies. FedEx, which at the time only offered air services, was under pressure from UPS which offered both air and ground services. By acquiring RPS, FedEx would get a fully fledged ground network to complement its existing air services. The acquisition of Caliber System was finalized in January 1998.

In preparation for this major acquisition, FedEx had reorganized as a holding company, FDX Corporation, in October 1997. When its acquisition of Caliber was finalized, FDX was the parent of both FedEx and Caliber's subsidiaries. It then embarked on significant reorganization to merge its existing business with the new subsidiaries. As part of this effort, it made broad changes to branding for the new acquisitions in 2000. FDX Corporation changed its name to FedEx Corporation, Federal Express was renamed FedEx Express, RPS became FedEx Ground, Caliber's same-day-critical trucking subsidiary, Roberts Express, became FedEx Custom Critical, and its LTL freight carrier, Viking Freight was re-branded FedEx Freight in 2001.

FedEx Ground launched a US residential delivery service, FedEx Home Delivery Service, in 2000. It was later renamed FedEx Home Delivery. In 2004, FedEx acquired New Berlin, Wisconsin-based parcel consolidator Parcel Direct from magazine and catalog printer Quad Graphics for $120 million. Following the acquisition, Parcel Direct was renamed FedEx SmartPost and became a subsidiary of FedEx Ground.

On January 14, 2013, FedEx named Henry Maier CEO and President of FedEx Ground, to take effect after David Rebholz retired on May 31, 2013.