Updated project metadata. Tissue morphogenesis requires the spatial control over actomyosin contractility to drive cell shape changes. How developmental patterning information controls cell mechanics is poorly understood. In the Drosophila embryo ectoderm, Myosin-II is enriched at the interface between antero-posterior neighboring cells, leading to planar polarized cell intercalation. G protein-coupled receptors (GPCRs) are required for planar polarized Myosin-II activation at junctions and Toll receptors provide a positional code underlying this process. How Toll receptors polarize actomyosin contractility remains unknown. Here we report that cells expressing different levels of a single Toll receptor Toll-8 activate Myosin-II at their interface. Surprisingly, the Toll-8 intracellular domain is not required for signaling at cell interfaces suggesting signaling by proxy. We found that Toll-8 forms a molecular complex with the adhesion GPCR Cirl/Latrophilin that is required for Toll-8 dependent junctional Myosin-II activation. Strikingly, the interfaces between Cirl expressing and cirl mutant cells also activate Myosin-II suggesting that Toll-8 induces Cirl asymmetric signaling at cell interfaces. We further showed that Toll-8 recruits Cirl both in trans and in cis, inducing asymmetric Cirl localization at the boundary of the Toll-8 expression domain. Finally, we found that Toll-8 and Cirl exhibit dynamic interdependent planar polarization when neighboring cells express different levels of Toll-8. Through this feedback, Toll-8 and Cirl self-organize planar polarized signaling.