• Packetized Elementary Stream, part of the MPEG communication protocol
• Party of European Socialists
• Payment for Ecosystem Services
• PES, the film director and animator
• Peoples Education Society, the educational organization
• Photoemission(Photoelectron) spectroscopy in chemistry
• Polyester, an artificially produced organic chemical that is spun and woven to make fabric.
• Polyethersulfone, a thermoplastic polymer
• Potential energy surface, in physics and chemistry
• Pro Evolution Soccer, a multi-platform game
• Programmed electrical stimulation, a type of electrophysiologic study
• Providence Elementary School, an elementary school in Chesterfield County, VA
• Psychiatric Emergency Services
• Price elasticity of supply in Economics
• Proposed Encryption Standard
• PULHHEEMS Employment Status, an index within the British Armed Services that determines whether a given soldier/employee can take part in a given operational posting.

Pes can be:

• Pes (zoology), Latin for "foot" (body part), thus used in anatomy to mean "foot" (or analogous body part)
• Pes (length), a Roman unit of length measurement roughly corresponding with a foot
• Pes (village), a former urban-type settlement in Novgorod Oblast, Russia; since 1999—a village