Scientific research shows that just thinking about a good friend can make people feel less stressed about their everyday problems. Other studies show that people with intact friendships are less stressed and have greater self-esteem. Other research indicates that friendships can even offset broken family relationships. This may also have something to do with the very nature of the friendship, because by its essence, friendships are the only human relationships that do without legal regulations, official founding rites, and mutual obligations. What a friendship looks like, why and how long it works, is negotiated only between the participants. At the same time, science is divided in terms of how exactly friendship should be defined. It is undisputed, however, that in classical Greek philosophy, friendship was clearly higher than love. Particularly in times of increasingly unstable couple and family relationships, increasing loneliness in old age—especially in Western cultures—and cultural and religious heterogeneity, friendship concepts are being examined more closely for their social value in the most diverse contexts. Additionally, the advent of AI companions has opened new dimensions in understanding friendships, where machines simulate human-like emotional bonds, offering companionship and emotional support. This chapter examines the question of what friendship is, to what extent it can be understood as a specific form of love relationship based on Aristotle, what its characteristics are, and to what extent it is universal or whether cultural differences can be described.