An apparatus for monitoring deposition rate, an apparatus including the same, for depositing an organic layer, a method of monitoring deposition rate, and a method of manufacturing an organic light emitting display apparatus using the same, are provided. The deposition rate monitoring apparatus for measuring deposition rate of a deposition material discharged from a deposition source, includes: a light source for irradiating light having a wavelength within a photoexcitation bandwidth of the deposition material; a first optical system for irradiating the light emitted from the light source toward the discharged deposition material; a second optical system for collecting the light emitted from the deposition material; and a first light sensor for detecting the amount of the light which is emitted from the deposition material and collected in the second optical system.