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Eocene volcanic rocks from the Central Sakarya Zone in the north of the İzmir-Ankara suture zone (IASZ) are predominantly intermediate-acidic lava flows and pyroclastics that crop out with a W-E orientation. The volcanic rocks include Bozaniç lavas, agglomerates, İğdir lavas, and Kapıkaya tuffs. The Bozaniç lavas contain plagioclase, hornblende, clinopyroxene, and biotite, whereas the İğdir lavas consist of plagioclase, hornblende, biotite, and quartz. According to the total alkali-silica (TAS) diagram, the Bozaniç lavas are mainly composed of andesite and dacite, with one sample of trachyandesite, whereas the İğdir lavas mainly contain dacite and minor andesite. Bozaniç and İğdir lavas exhibit moderate-to high-K calc-alkaline character. Major oxide and trace element variations suggest the effects of fractional crystallization in the evolution of the volcanic rocks. N-type midocean ridge basalt (MORB) normalized trace element patterns of the lavas exhibit enrichment in large ion lithophile elements (LILEs; K, Rb, Ba, Th) and depletion in high field strength elements (HFSEs; Zr, Ti, Y). In addition, the chondritenormalized rare earth element (REE) plots of the rocks show moderately enriched and nearly concave-shaped patterns (La N /Yb N = 5.4-17.6 for the Bozaniç lavas and 6.5-13.1 for the İğdir lavas), suggesting clinopyroxene (Cpx) and hornblende dominated fractionation. Negative Eu anomalies in the acidic lavas reveal plagioclase fractionation. Some trace element ratios of the lavas demonstrate a subduction signature and crustal contamination in the generation of the parent magma(s). Multi-dimensional tectonic discrimination diagrams suggest that the studied volcanic rocks have developed in a collisional setting.