This study was conducted to determine the effects of altitude and aspect on the wood anatomical characteristics of oriental beech (Fagus orientalis Lipsky) in Mountain (Mt.) Uludağ. A total of 36 samples from 36 trees, one sample per tree, were collected from six different elevations separated by 200 m (550–1550 m) on both the north and south aspects of Mt. Uludağ. Vulnerability, mesomorphy, and xeromorphy ratios were calculated for each sample. Duncan’s test and cluster analysis were conducted using all measurements related to the vessels, rays, and fibers of each sample. The results indicated that the diameters and lengths of vessel elements increased from the lower to upper altitudes when the vessel frequency decreased. The widths of narrow rays decreased from 550 to 1550 m, whereas the ray frequency per millimeter increased. The fiber lengths, the wall thickness of fibers, and the fiber lumen widths increased from 550 to 1550 m in both aspects. Moreover, according to cluster analysis, the groups and subgroups separated depending on elevations. Vulnerability and mesomorphy ratios increased significantly in relation to the elevation of up to 1550 m in both aspects, whereas the xeromorphy ratio decreased inversely. An altitude of 1550 m on the north aspect provided the best mesomorphic conditions, whereas an altitude of 550 m on the south aspect was dominated by an arid climate for the beeches. Finally, altitude was more effective than aspect on the anatomical features of the beech wood in Mt. Uludağ.