Thread seal tape (also known as PTFE tape, Teflon tape, or plumber's tape) is a polytetrafluoroethylene (PTFE) film tape commonly used in plumbing for sealing pipe threads. The tape is sold cut to specific widths and wound on a spool, making it easy to wind around pipe threads. Thread seal tape lubricates allowing for a deeper seating of the threads, and it helps prevent the threads from seizing when being unscrewed.

Typically the tape is wrapped around a pipe's male threads three times before it is screwed into place. It is wrapped in the same direction the male threads go for tightening. The tape is commonly used commercially in applications including pressurized water systems, central heating systems, and air compression equipment.