A method of operating a storage device including a neural network processor includes outputting, by a controller device, a trigger signal instructing the neural network processor to perform a neural network operation in response to a command from a host device, requesting, by a neural network processor, target model data about parameters of a target model and instruction data for instructing the neural network operation to a memory device storing the target model data and the instruction data in response to the trigger signal, receiving, by the neural network processor, the target model data and the instruction data from the memory device and outputting, by the neural network processor, inference data based on the target model data and the instruction data.