The use of firearms, their frequency, and legitimacy through self-defence and extreme necessity are socially relevant in Czechia and Slovakia. Legal firearm ownership for defence purposes impacts overall social security, influenced by factors like firearm legislation, cultural traditions, legal awareness, and violent crime rates. Understanding this issue requires considering subjective interpretations, even among security experts. This paper explores the theoretical foundations of self-defence and extreme necessity from criminal law, alongside practical implications supported by police statistics on violent crimes involving firearms in Czechia and Slovakia. It also includes a comparison with selected EU countries. The authors’ research uses a questionnaire to assess attitudes towards choosing defensive firearms, preparation for firearms licensure, and potential support for state security forces. The findings provide insights into legal firearm owners’ behaviours and attitudes toward defence and security. The study aims to contribute to a deeper understanding of firearm use for self-defence, correlating training, weapon preferences, and willingness to enhance state security.