In this study, the genetic relatedness of 15 walnut accessions adapted to the Lahijan region of Guilan province, Iran was analyzed by morphological characters. The traits like growth habit, leafing date, content of male flower, nut yield, nut weight, kernel weight, kernel percent, hard shell thickness, nut length, and nut thickness. The coefficient of genetic diversity obtained for nut yield was high, indicating high diversity of the samples under study for this trait. The association and correlation between the traits in most cases were significant at ?=0.01 and ?=0.05. Simple correlation analysis showed that nut yield had significant and positive correlation with weight of the nut, the weight and the length of the kernel and the thickness of hard shell (r= 0.762, 0.758, 0.558, respectively). Also, the association between nut yield and hard shell thickness was negative and significant (r=-0.741). Genetic diversity was assessed between and within accessions using statistical analyses including Coefficients of Variation (CV), Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). The results obtained from cluster analysis placed the accessions in three separate groups. Principal component analysis indicated that the first and second components explained 69.6% of all variance. This grouping was completely consistent with cluster analysis. In addition, the results indicated high diversity based on the morphologic indices, which requires greater, closer attention to the region’s native walnuts for subsequent breeding programmes.