Cannabidiol (CBD) is one of the most important cannabinoids found in hemp plants, having numerous applications in the pharmaceutical and food industries. Due to its low solubility in water, CBD is usually supplied in hydrophobic solvents. The present work investigated the solubility of CBD in ten plant oils and various systematically designed hydrophobic eutectic systems (ESs). The CBD solubility was found to correlate with the molecular weight and structure of the oils and ES constituents. CBD was more soluble in medium-chain triglyceride oils than in oils containing long-chain unsaturated fatty acids. Moreover, the CBD solubility was found to be higher in ESs than in oils. The conductor-like screening model for realistic solvents (COSMO-RS) was then applied to estimate the CBD solubility in oils and ESs. COSMO-RS did not provide satisfactory predictions of the CBD solubility in oils, possibly because oils were regarded as simple mixtures of fatty acids. On the other hand, COSMO-RS predicted well the CBD solubility in ESs. This work showed that newly-designed hydrophobic ESs could be alternative green solvents for CBD formulation and extraction.