Axon guidance receptors modulate the growth cone cytoskeleton through signaling pathways that are not well understood. Here, we describe the C. elegans unc-115 gene, which encodes a candidate cytoskeletal linker protein that acts in axon guidance. unc-115 mutants have defects in a subset of axons, particularly as the affected axons change environments during outgrowth. The unc-115 gene encodes a putative actin-binding protein that is similar to the human actin-binding protein abLIM/limatin; it has a villin headpiece domain and three LIM domains that could mediate protein interactions. unc-115 is expressed in neurons during their development and is required cell-autonomously in certain neurons for normal axon guidance. We propose that UNC-115 modulates the growth cone actin cytoskeleton in response to signals received by growth cone receptors.