The present disclosure is related to an imaging device, an imaging system, and a moving body. The imaging device according to an exemplary embodiment includes: a plurality of pixels and a connection transistor. Each of the plurality of pixels includes a photoelectric conversion unit, an amplification transistor that outputs a signal based on an electric charge generated in the photoelectric conversion unit, and a selection transistor that connects a source of the amplification transistor and an output line. The connection transistor includes two nodes, a conducting state between the two nodes being controlled by a signal supplied to a gate of the connection transistor. One of the two nodes is connected to the source of the amplification transistor of a first pixel included in the plurality of pixels. The other is connected to the source of the amplification transistor of a second pixel included in the plurality of pixels.