© 2022 Elsevier Ltd and INQUAThe main aim of the study is to determine the paleoenvironmental and climatic changes in the Engir Lake (Central Anatolia Region of Türkiye) and its surroundings during the last 1090 years. A total of 63 sub-samples with a resolution of 4 cm were obtained from the 263 cm-long sediment core, which was taken from a site away from the current and where the deterioration was the least. Based on fossil diatoms, important data have been obtained about the Medieval Warm Period (MWP), the Little Ice Age (LIA), and the Industrial Period (IP). The MWP corresponds to between ca. AD 860–1240 cal yr in the Engir Lake and its surroundings. In this study, the MWP is generally described as a warm and wet period characterized by a relatively high water level recorded between ca. AD 1110–1240 cal yr. Although the first evidence of the onset of dry conditions occurs between ca. AD 1260–1320 cal yr, the first characteristic impact of the LIA on Engir Lake is generally observed between ca. AD 1350–1380 cal yr. This first dry period in Engir Lake corresponds to the global Wolf Minimum, while ca. AD 1490–1530 cal yr corresponds to the Spörer Minimum and ca. AD 1620–1690 cal yr corresponds to the Maunder Minimum. During these periods, low water levels were recorded in the lake with aerophile taxa dominating. Between these dry phases, the core also recorded relatively wet phases. These wet phases occurred at ca. AD 1390–1480, AD 1530–1620, and AD 1690–1760 cal yr, respectively. After ca. AD 1890 cal yr, the pollution of the lake increased due to the industrial activities in the vicinity of Engir Lake, and aquatic plants developed in the vicinity of the lake with increasing nutrient input. This study is an important record for understanding the past, as there has not yet been a relatively detailed study on LIA and MWP through fossil diatoms in Türkiye.