This study presents the fracture behavior of synthetic fiber-reinforced structural lightweight aggregate concrete (SynFR-SLWAC) by experimental and analytical studies. Experimental studies include testing of 15 specimens for understanding mode-1 fracture response. Analytical studies include developing multilinear stress-crack width relations through inverse analysis. SynFR-SLWAC is made using sintered fly ash aggregate (SFA) with varying volume fractions of monofilament macro synthetic (0.2%, 0.4%, and 0.6%) and a small fraction of micro synthetic fibers (0.02%). The effect of synthetic fiber addition on the crack arresting mechanisms of SynFR-SLWAC is studied using the digital image correlation (DIC) technique. The stress-crack width relations are obtained from the experimental load-crack mouth opening displacement (CMOD) curves using inverse analysis. Additionally, empirical equations are proposed for predicting the stress-crack width relationship for SynFR-SLWAC with different fiber volume fractions. Fracture energy increased significantly with an increase in fiber volume dosage at larger values of crack width. Hinge width of SynFR-SLWAC reduced when compared to normal density concrete made of natural coarse aggregates. © 2021 American Society of Civil Engineers.