<p>Thyroid diseases are a pressing issue in modern medicine, making it crucial to develop new pharmacological agents with effective therapeutic properties. This review analyzes the latest research on the role of various compounds of the essential trace element selenium in maintaining normal thyroid hormone function. In recent decades, numerous studies have been published demonstrating the diverse therapeutic properties of selenium compounds of various origins, demonstrating the effectiveness of this trace element in combating diseases of various etiologies. It is known that the thyroid gland, an important endocrine organ, regulates the hormonal balance of the key hormones thyroxine and triiodothyronine, and the enzymes that play a key role in this regulation are selenium-containing deiodinases. This review presents the latest data on this regulation, as well as the role of other selenoproteins in mitigating thyroid pathological processes. In addition, the latest developments in nanoselenium-based drugs are presented and the mechanisms for regulating various thyroid pathologies using selenium-containing nanoparticles and nanocomplexes are described. The role of organic and inorganic selenium-based drugs is also described. Thus, the information presented in this review allows us to understand the latest trends in the development of new selenium-based drugs for maintaining normal thyroid function.</p>