PW or pw may stand for:

• Palau, an island nation in the Pacific Ocean; Palau's postal abbreviation is PW
• an abbreviation for password
• Pauly-Wissowa, a German encyclopedia of classical scholarship
• Petawatt, a unit of power
• Picowatt , a unit used for measuring noise levels, commonly abbreviated pW
• Piggly Wiggly, a U.S. supermarket chain
• Politechnika Warszawska, the Warsaw University of Technology, in Poland
• Power window, an automobile window which is raised and lowered by a switch
• the IATA code for Precision Air based in Tanzania
• PricewaterhouseCoopers, an international accounting and business consulting firm
• Prisoner of war, a soldier who is imprisoned by an enemy, more commonly abbreviated P.O.W.
• Protest Warrior, a movement of primarily conservatives and libertarians, counter-protesting mostly anti-war activists and anarcho-communistic groups.
• Providence and Worcester Railroad
• Publishers Weekly, a magazine covering the book publishing industry