Layer may refer to:
A layer of archaeological deposits in an excavation
A layer hen, a hen kept to produce eggs
Layered clothing, wearing multiple layers of clothing
Fiction
Layer, a female Maverick Hunter in the Mega Man X series
Science
Stratum, a layer of rock or soil with similar composition
Thermocline, a layer of temperature within an area of water
Technology
Computing
Abstraction layer, a way of hiding the specifications of a function
OSI model layers
Internet protocol suite layers
2D computer graphics#Layers, layers in two-dimensional (2D) computer graphics
Layers (digital image editing), used in digital image editing to separate different elements of an image