Piki Mach'ay (Quechua piki flea, mach'ay cave, "flea cave", also spelled Pikimachay, Piquimachay, where machay means "drunkenness", "to get drunk" or "a spindle packed with thread") is an archaeological site in the Ayacucho Valley of Peru. Radiocarbon dates from this cave give a human presence ranging from 22,200 to 14,700 years ago, but this evidence has been disputed and a more conservative date 12,000 years BCE seems possible.

Richard S. MacNeish was the first archaeologist to explore Piki Mach'ay. Evidence of long-term human occupation has been found at the site, though that evidence still remains controversial.

The cave is part of the Ayacucho complex, a culture defined by several cave sites including Jaya Mach'ay ("pepper cave").