A search for the flavor-changing neutral-current decay Λ+c→pμ+μ− is reported using a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb Collaboration. No significant signal is observed outside of the dimuon mass regions around the ϕ and ω resonances, and an upper limit is placed on the branching fraction of B(Λ+c→pμ+μ−)<7.7(9.6)×10−8 at 90%(95%) confidence level. A significant signal is observed in the ω dimuon mass region for the first time.Received 21 December 2017DOI:https://doi.org/10.1103/PhysRevD.97.091101Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.© 2018 CERN, for the LHCb CollaborationPhysics Subject Headings (PhySH)Research AreasFlavor changing neutral currentsLeptonic, semileptonic & radiative decaysPhysical SystemsBaryonsTechniquesHadron collidersParticles & Fields