拟亲属关系是以亲属的称谓称呼没有血缘关系的人，以及把他们当作亲属般对待的人际关系。创建这种关系的人称为拟亲属。

大部份人类学者观察到拟亲属关系担当着协助或介入传统亲属关系，但不会完全取代亲属。

Janet Carsten在回应施奈特（David M. Schneider）在1984年发表的《亲属制度研究批判》（A Critique of The Study of Kinship）所提及的符号式亲属关系（Symbolic Kinship）时提出「关联」（relatedness）的概念。

在东亚，人们常常以亲属称谓去称呼他人，例如中国人常以「大哥」、「大姐」称呼不相识的同辈或年纪较自己大的同辈朋友，以「大叔」、「阿姨」称呼无血缘关系的长辈，以「伯父」、「伯母」称呼朋友的父母；在古代至近代，夫妻也常会兄妹相称。西方文化中人们会称密友的父母为「aunt」或「uncle」。把密友称为「兄弟」或「姊妹」在东西方也很常见（甚或「情同手足（兄弟）或「亲如姊妹」」）。某些学校社团和组织也会把成员称为「兄弟」或「姊妹」。

Fictive kinship is a term used by anthropologists and ethnographers to describe forms of kinship or social ties that are based on neither consanguinal (blood ties) nor affinal ("by marriage") ties, in contrast to true kinship ties. To the extent that consanguinal and affinal kinship ties might be considered real or true kinship, the term fictive kinship has in the past been used to refer to those kinship ties that are fictive, in the sense of not-real. Invoking the concept as a cross-culturally valid anthropological category therefore rests on the presumption that the inverse category of "(true) kinship" built around consanguinity and affinity is similarly cross-culturally valid. Use of the term was common until the mid-to-late twentieth century, when anthropology effectively deconstructed and revised many of the concepts and categories around the study of kinship and social ties. In particular, anthropologists established that a consanguinity basis for kinship ties is not universal across cultures, and that—on the contrary—it may be a culturally specific symbol of kinship only in particular cultures (see the articles on kinship and David M. Schneider for more information on the history of kinship studies).