Gift tax is a fiscal mechanism imposing a levy on the gratuitous transfer of assets between living individuals (inter vivos transfers), typically borne by the donor. As an academic concept and research area, it investigates the economic, legal, and behavioral dimensions of taxing wealth transfers made without full consideration. Research in this domain examines its structural components, such as exclusion thresholds, valuation rules, and donor liability; its behavioral impacts on saving, investment, and philanthropic decisions; its role in wealth redistribution and intergenerational equity; and its interaction with other components of the transfer tax system, notably the estate tax. Key characteristics studied include the principle of donor liability, the application of annual and lifetime exclusions, and its objective within the broader tax policy framework. Its significance as a research topic stems from its influence on capital formation, philanthropic activity, and wealth concentration, positioning it as a critical subject within public finance, law, and applied economics.