We present the first search for CP violation in top quark-antiquark pair events. The search is based on asymmetries in T-odd triple product correlation observables, where T is the time reversal operator. The analysis is based on a sample of proton-proton collisions at sqrt(s)=8TeV collected by the CMS experiment, corresponding to an integrated luminosity of 19.7fb^-1. The analysis is performed with events having exactly one electron or muon and at least four jets. The T-odd observables are measured using the linearly independent four-momentum vectors associated with top quark production and decay. The measured asymmetries exhibit no evidence for CP-violating effects, in agreement with the standard model prediction.