© The Author(s) 2020. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits redistribution, commercial and noncommercial, provided that the article is properly cited.This research was conducted to investigate some quality parameters of nuts of walnut (Juglans regia L.) 'Chandler' grown at different altitudes. Studies were conducted in E§me Town, U§ak Province, in three different villages situated at an average altitude of 650 m, 800 m, and 900 m. Studies were conducted in Karaahmetli, Takmak, and Ye§ilkavak villages in the 2012-2013 production year and orchards with similar soil and topography characteristics were selected. Plant protection, plant production, and other cultivation practices in the sampled orchards were also noted and orchards with the same attributes were selected. During the harvesting period, regular measurements were taken to determine correct time for harvesting. Nuts were hand-harvested when the color of the membrane separating the kernel and outer parts turned brown. A total of 3540 nuts were randomly selected and harvested from the three orchards and 15 of those were randomly selected for further analysis. Nut weight, internal (kernel) weight, shell thickness, kernel color, dry matter, moisture, ash, protein, oil, mineral matter, and free fatty acid composition were determined. Results showed that the site altitude significantly influences walnut's quality and it is highly important to consider the site altitude as a factor before planting new orchards. Results showed that nut height, nut width, nut length, nut weight, kernel weight, shell thickness, oil content, phosphorus content, magnesium content, oleic acid, and linolenic acid increase with an increase in altitude. On the other hand, kernel ratio, total nitrogen, and protein content were found to decrease with increasing site altitude.