Princess Patricia's Canadian Light Infantry (PPCLI, generally referred to as the Patricia's) is one of the three Regular Force infantry regiments of the Canadian Army of the Canadian Armed Forces. Formed in 1914, it is named for Princess Patricia of Connaught, daughter of the then-Governor General of Canada. The regiment is composed of three battalions, for a total of 2,000 soldiers. The PPCLI is the main lodger unit of Canadian Forces Base (CFB) Edmonton in Alberta and CFB Shilo in Manitoba, and attached to 3rd Canadian Division; as such, it serves as the "local" regular infantry regiment for much of Western Canada. The Loyal Edmonton Regiment (LER), a Reserve Force battalion, is affiliated with the PPCLI but is not formally part of it. As part of this affiliation, the LER carries the designation '4th Battalion, Princess Patricia's Canadian Light Infantry'.

The regiment is a ceremonial structure, and the three battalions are independent operational entities, under the 1 Canadian Mechanized Brigade Group (1 CMBG). Although the regimental name includes the phrase light infantry, two of its battalions are mechanized infantry, and the unit has never been organized as a traditional light infantry regiment.

The PPCLI was raised on the initiative of Captain Andrew Hamilton Gault in 1914, to participate in the Canadian war effort for the First World War. It was the first Canadian infantry unit to enter the theatre of operations, arriving in France on December 21, 1914. The regiment has also participated in the Second World War, the Korean War and the War in Afghanistan, as well as in numerous NATO operations and United Nations peacekeeping missions. The regiment has received 39 battle honours, three Commander-in-Chief Unit Commendations and the United States Presidential Unit Citation.