Wereport the first high-resolution (20–50 years) mid- to late Holocene pollen records fromLake Teletskoye, the largest lake in the Altai Mountains, in south-eastern West Siberia. Generally, the mid- to late Holocene (the last 4250 years) vegetation of the north-eastern Altai, as recorded in two studied sediment cores, is characterised by Siberian pine–spruce–fir forests that are similar to those of the present day. A relatively cool and dry intervalwith July temperatures lower than those of today occurred between 3.9 and 3.6 ka BP. The widespread distribution of open, steppe-like communitieswith Artemisia, Chenopodiaceae and Cyperaceae reflects maximumdeforestation during this interval. After ca. 3.5 ka BP, the coniferous mountain taiga spread significantly,withmaximumwoody coverage and taiga biome scores between ca. 2.7 and 1.6 ka BP. This coincides wellwith the highest July temperature (approximately 1 °C higher than today) intervals. A short period of cooling about 1.3–1.4 ka BP could have been triggered by the increased volcanic activity recorded across the Northern Hemisphere. A new period of cooling started around 1100–1150 CE, with the minimum July temperatures occurring between 1450 and 1800 CE.