A bromance is a very close friendship between two heterosexual men, classically two single heterosexual men. Men in a bromance are sometimes said to be “bromosexual,” and they may be accused of having “man crushes,” even though their relationship is not, in fact, sexual in nature. Close friendships between men have been a fact of life for centuries, but the bromance appears to be especially common today, thanks to the large numbers of people who may remain single for an extended period of time, rather than marrying or becoming involved in relationships.

Men in a bromance have typically known each other for a very long time, and they share immense love, respect, and affection for each other. It is common for a bromance to express itself in the form of physical affection such as play wrestling, hugging, and other activities, but the relationship also goes much deeper than surface physical expressions of friendship. Often, the men become close with each other's families, spending time with them and considering themselves to be almost like members of the family. It is also not uncommon to see men in a bromance living together, taking advantage of their close friendship to save money on the rent.

All sorts of activities can take place under the umbrella of a bromance, although typically there is a heavy focus on excluding women. Men in a bromance may drink together, go to sporting events, participate in sports, and share other life experiences with each other, sometimes in the company of other men and sometimes as a couple. Many bromances start in college, a period of increased socialization, and they endure well into late life, even after the men find long-term heterosexual partners.

Many cultures have a tradition of homosociality, or friendships between people of the same sex. Classically, homosocial relationships fill the social gap left by not engaging in sexual relationships, and as a result they tend to peter out at the time of marriage. However, the strong bonds formed in homosocial relationships do endure, with the partners in a homosocial relationship spending time with each other's new families, helping each other out when needed, and sometimes entering into business partnerships with each other.

The concept of a bromance is derided in some communities, especially those where such relationships are viewed as unmanly. In regions where the stigma against homosexuality is strong, men in a bromance may find themselves the subjects of mockery and derision, and they may be told to prove their manhood if they want to stay in their social circles. In other areas of the world, bromances are widely accepted and sometimes actively cultivated, as a loyal companion can be a valuable thing to have.