A touch sensor includes a substrate, sensing electrodes (SEs), and sensing lines (SLs). The substrate includes a sensing area (SA) and a peripheral area outside the SA. The SEs overlap the SA. The SLs overlap the peripheral area, are respectively connected to the SEs, and include first SLs (FSLs) alternatingly arranged with second SLs (SSLs). Each of the SLs includes: a first metal layer (FML) on the substrate; a first insulating layer (FIL) on the FML and including a first contact hole (FCH) exposing the FML; and a second metal layer (SML) on the FIL and connected to the FML through the FCH. A width of the FML of each of the FSLs is different from a width of the FML of each of the SSLs. A width of the SML of each of the FSLs is different from a width of the SML of each of the SSLs.