ALP or AlP may refer to:

• AlP, molecular formula for aluminium phosphide
• Alkaline phosphatase, an enzyme

Alp may refer to:

• Alp, a high mountain, especially of the Alps
• Alp, an alpine pasture, especially in Switzerland
• Alp (Alip), a Turkish honorific
  • Alp (name)
• Australian Labor Party
• Alp (folklore), a nightmare creature originating in German folklore
• Alp, Spain, a town and municipality in Catalonia
• Alp 2500, a ski resort in Catalonia, Spain
• Alp (river), a river in the Swiss canton of Schwyz

Aluminium phosphide (aluminum phosphide) is a highly toxic inorganic compound with the chemical formula P used as a wide band gap semiconductor and a fumigant. This colorless solid is generally sold as a grey-green-yellow powder due to the presence of impurities arising from hydrolysis and oxidation.