ptx may refer to:
- ptx, a Unix command-line utility producing a permuted index
- Pertussis toxin, an inhibitor of G-protein coupled receptors
- Picrotoxin, a poisonous crystalline plant alkaloid
- Pneumothorax, a medical condition affecting the lungs
- Parallel Thread Execution, an intermediary assembler language between high level code and that which is sent to the GPU (in Nvidia's CUDA programming model)
- Plano, Texas, a city located within the metropolitan area commonly referred to as the Dallas–Fort Worth metroplex.
- Pentatonix, an a cappella group that won the NBC competition The Sing-Off in 2011.