In the field of soft robotics, there is a lack of closed loop controls. This is often because there is not a need like how in soft grippers, the compliant materials naturally deform around objects to grasp. However, for more complex robots and functions, feedback controls will be necessary. This necessitates soft and stretchable sensors to be embedded in or on the body. Looking to inspiration from animals, distributed exteroception and proprioception are crucial to both understand the shape of the soft robot and how it is interacting with the environment. Although a variety of soft sensors using piezoresistive, capacitive, piezoelectric, triboelectric and magnetic properties are being researched, I focus on optical sensors as they can produce more information dense signals and are resistant to electromagnetic interference. This dissertation explores the design, fabrication, characterization, and use of stretchable optical sensors in soft bodies. In my first work, I present a network of stretchable optical fibers that couple light between lightguides embedded in a soft structure to measure the location and degree of applied external forces and internal strains. Next, I show how different geometries of lightguide networks can be designed to measure specific kinds of deformation such as twisting and bending. Third, I present how strain in textiles can be measured noninvasively by stitching optical fibers onto them. And last, I present a robotic flesh composed of soft materials that encode location and magnitude of applied forces and temperature into an optical signal for haptic sensing.