Essential oils of 25 indigenous populations of Dalmatian sage (Salvia officinalis L.) that represent nearly half of native distribution area of the species were analyzed. Plantlets collected from wild populations were grown in the same field under the same environmental conditions and then sampled for essential-oil analysis. The yield of essential oil ranged from 1.93 to 3.70% with average of 2.83%. Among the 62 compounds detected, eight (cis-thujone, camphor, trans-thujone, 1,8-cineole, β-pinene, camphene, borneol, and bornyl acetate) formed 78.13-87.33% of essential oils of individual populations. Strong positive correlations were observed between camphor and β-pinene, β-pinene and borneol, as well as between borneol and bornyl acetate. The strongest negative correlation was detected between camphor and trans-thujone. Principal component analysis (PCA) on the basis of eight main compounds showed that first main component separated populations with high thujone content, from those rich in camphor, while the second component separated populations rich in cis-thujone from those rich in trans-thujone. Cluster analysis (CA) led to the identification of three chemotypes of S. officinalis populations: cis-thujone; trans-tujone, and camphor/β-pinene/borneol/bornyl acetate. We propose that differences in essential oils of 25 populations are mostly genetically controlled, since potential environmental factors were controlled in this study.