Tensile strength and creep behavior of a two-dimensional (2D) laminate carbon-carbon composite (C/C) were examined from room temperature to 2773 K in an inert atmosphere. The tensile strength of the C/C was monotonically enhanced with increasing test temperatures. In particular, significant improvement was observed at temperatures higher than 1773 K. In this temperature range, nonlinear stress-strain curves were observed at low deformation rates, but with increasing test speed, the stress-strain curves became linear until total fracture. The source of the apparent nonlinearity was thus concluded to be creep deformation, Which appeared from 1773 K. Two ruling mechanisms for the strength enhancement of the C/C at elevated temperatures were identified. The first source was degassing of absorbed water, which had a dominant influence on the strength enhancement up to 1773 K. The second was creep deformation. This phenomenon was notable at temperatures higher than 1773 K, and produced much larger enhancement than the degassing.