Local protein synthesis is rapidly regulated by extrinsic signals during neural wiring but the translational control mechanisms remain elusive. Here, we show that the guidance cue Sema3A, but not Slit1, elicits precise spatiotemporal control of the phosphorylation of the translation initiation factor, eIF2α, in axonal growth cones via the Unfolded Protein Response (UPR) kinase PERK. Strikingly, in contrast to the canonical UPR signaling, we find that the Sema3A-induced eIF2α phosphorylation bypasses the conventional global translational repression and underlies a burst in axonal protein synthesis, mediated by differential eIF2B activity. Ultrasensitive proteomics on somaless axons reveals a subset of 75 proteins translationally regulated via Sema3A-p-eIF2α, including several proteostasis- and actin cytoskeleton-related nascent proteins. Finally, in vivo experiments provide evidence that eIF2α phosphorylation drives the formation of the retinotectal axon projection. Thus, specific extracellular cues can trigger non-canonical PERK-eIF2α-eIF2B signaling leading to subcellular dynamic remodeling of the nascent proteome required for neural wiring.