Hemp (Cannabis sativa L.) is a rapidly growing plant with multipurpose uses, and the optimal combination of yield and quality of hemp products (fibers, inflorescences, or seeds) may provide economic opportunities to uncover the full spectrum of its capabilities. The presented experimentation took place over seven years (2017–2023) in Greek climatic conditions for fourteen (14) registered monoecious and dioecious varieties. It can be concluded that the production of biomass, fiber, and seed weight were different not only between varieties but also from year to year. Despite significant variation between harvest years in biomass yield, the extracted fiber was relatively constant. Moreover, not only the dioecious varieties but also the monecious varieties could be effectively grown for biomass production in Greece. Regarding fiber production, monoecious varieties had the highest yields, apart from the dioecious Kompolti variety, which was the most fiber-productive. Under the experimentation conditions, early flowering varieties were most suited for seed production, and the KC Dora variety produced the heavier seeds. Generally, the Futura 75 variety was one of the most productive varieties for biomass and seed weight, while the Bialobrzeskie variety produced the greatest amounts of fiber.