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. The tape also works as a deformable filler and thread lubricant, helping to seal the joint without hardening or making it more difficult to tighten, and instead making it easier to tighten. It also protects the threads of both pieces from direct contact with each other and physical wear, and helps seal and prevent leaks from the connection.

Typically the tape is wrapped in the same direction the male threads go for tightening, and commonly used commercially in applications including pressurized water systems, central heating systems, and air compression equipment.