Results are presented from a search for large, extra spatial dimensions in events with either two isolated muons or two isolated electrons. The data are from proton–proton interactions at s=7TeV collected with the CMS detector at the LHC. The size of the data sample corresponds to an integrated luminosity of approximately 2fb−1. The observed dimuon and dielectron mass spectra are found to be consistent with standard-model expectations. Depending on the number of extra dimensions, the 95% confidence level limits from the combined μμ and ee channels range from Ms>2.4TeV to Ms>3.8TeV, where Ms characterizes the scale for the onset of quantum gravity.