We present a study of the lithium abundance of five pre-main sequence (PMS) double-lined binaries. These binaries are composed of weak-lined T Tauri stars having spectral types ranging from K3 to K7. For each binary, Lee (1992) has determined domains of spectral type and luminosity for the binary componenets. Lithium abundances in Local Thermodynamic Equilibrium (LTE) and non-LTE are then derived from the Li I lambda 6707 resonance line. Considering the entire range of spectral type and luminosity available to each binary component, we place an upper limit on lithium abundance differences between binary components of 1.0 dex. However, within the more limited range of spectral type and luminosity where a binary's component have theoretical mass ratios consistent with their dynamical mass ratios we find smaller abundance differences. For such pairs of components the lithium abundance differences are less than 0.4 dex for four of the binaries; for the binary 162814-2427 the upper limit remains 1.0 dex. We conclude that for each binary the components formed from similar material, and that the formation and early evolution of the binaries did not alter their relative lithium abundances. These results are also consistent with previous suggestions that effective temperature uncertainties are the origin of observed ranges of lithium abundances as large as 1 dex in star-forming regions. The mean non-LTE lithium abundance of the five binaries is log N(Li) = 3.1 +/- 0.4, very near the present cosmic abundance, although we find a higher lithium abundance of 3.8 +/- 0.3 for the binary P1540.