An inspection method includes generating first layout data including information on a shape of a first pattern group, generating second layout data including information on a shape of a second pattern group, obtaining a target image including images of the first and second pattern groups, and detecting a defect pattern from the target image by comparing the first and second layout data with the target image. The first pattern group, the second pattern group, and the defect pattern are provided at different heights from each other, from a top surface of a substrate.