PD1 may refer to:

• Prussian S 3 a 19th-century steam locomotive
• PD-1 the Programmed cell death protein 1 receptor

• Sewe language
• Sewell A. Peterson
• Sewell Collins
• Sewellia
• Sewell, James
• Sewell mill creek
• Sewell Point
• Sewells Group
• Sewells Road Bridge
• Sewells Road Suspense Bridge
• Sewells Road Suspension Bridge
• Sewell-Thomas Stadium
• Sewerby House
• Sewer Dosing Unit
• Sewer fly
• Sewer gator
• Sewer overflow (disambiguation)
• Sewerstal Tscherepowez
• Sewerthermal
• Sewer treatment
• Sewer treatment plant
• Sewer vine
• Seweryn
• Seweryna Szmaglewska
• Seweryn Chajtman