Barley (Hordeum vulgare L.) is the fourth largest cereal crop in the world with extensive adaptability in diverse environments. There is increasing evidence that epigenetics contributes to plant evolution and adaptation. However, epigenetic variation in barley and their correlations with genetic variation remains largely unknown. In this study, we investigated epigenetic and genetic diversity in 48 Tibetan wild distribution (TWD) barley accessions, 24 Chinese cultivars (CC), and 24 foreign cultivars (FC) using DNA methylation-sensitive amplified polymorphism and simple sequence repeats. We found a relatively high level of epigenetic (I = 0.639 and h = 0.450) and genetic (I = 0.637 and h = 0.446) diversity in barley, and a significant correlation between epigenetic and genetic variation in barley (R² = 0.160, P < 0.001). No differences in genetic variation were observed among TWD, CC and FC populations. However, the TWD population had significantly higher epigenetic diversity (I = 0.607 and h = 0.424, P < 0.001) than both cultivated populations (FC: I = 0.584 and h = 0.402; CC: I = 0.544 and h = 0.372). Also, the TWD population had significantly higher average hemi-methylation (20.35%) and full-methylation (25.37%) levels than both cultivated populations (FC: 16.13% and 20.98%, respectively; CC: 15.98% and 18.95%, respectively). This study has provided valuable information on DNA methylation variation across diverse barley accessions and indicated that epigenetic variations might be another factor contributing to barley diversity.