The present technology relates to an image sensor, an electronic apparatus, a signal transmission system, and a control method that are capable of easily reducing adverse effects of a parasitic capacitance. An assist signal line is adjacent to a VSL and placed along the VSL, a signal output from a pixel flowing through the VSL, and a signal control unit causes a similar signal to flow through the assist signal line, the similar signal having a similarity to a signal that flows through the VSL. The present technology is applicable to, for example, an image sensor including a VSL through which a signal output from a pixel flows, and a signal transmission system including a transmission path through which a signal flows.