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The palaeolake evolution across the Tibetan Plateau and adjacent areas has been extensively studied, but the timing of late Pleistocene lake highstands remains controversial. Robust dating of lacustrine deposits is of importance in resolving this issue. This paper presents C-14 or optically stimulated luminescence (OSL) age estimates from two sets of late Quaternary lacustrine sequences in the Qaidam Basin and Tengger Desert (northeastern Tibetan Plateau). The updated dating results show: (1) the radiocarbon dating technique apparently underestimated the age of the strata of >30 ka BP in Qaidam Basin; (2) although OSL and C-14 dating agreed with each other for Holocene age samples in the Tengger Desert area, there was a significant offset in dating results of sediments older than similar to 30 ka BP, largely resulting from radiocarbon dating underestimation; (3) both cases imply that most of the published radiocarbon ages (e.g., older than similar to 30 ka BP) should be treated with caution and perhaps its geological implication should be revaluated; and (4) the high lake events on the Tibetan Plateau and adjacent areas, traditionally assigned to MIS 3a based on C-14 dating, are likely older than similar to 80 ka based on OSL chronology.