Stress monitoring using piezo-electric smart aggregate (SA) provides a useful way to assess damage in concrete structures. Although the feasibility has been verified in normal weight concrete (NWC), efforts are needed for lightweight concrete (LWC) due to the differences in meso-scale factors that is key for SA-based monitoring. In this paper, SA sensors were tested for monitoring stress using four identical LWC cylinders with six SAs embedded in each specimen subjected to typical loading paths and load levels. Based on the test results, the effects of the related meso-scale factors on the feasibility of monitoring were evaluated. After that, the sensors’ sensitivity curve and the extent of SA output randomness were quantified. It can be concluded that SAs have potential for monitoring stress in LWC structures during the entire damage process.