The immediate family is a defined group of relations, used in rules or laws to determine which members of a person's family are affected by those rules. It normally includes a person's parents, siblings, spouse, and children. It can contain others connected by birth, adoption, marriage, civil partnership, or cohabitation, such as grandparents, grandchildren, aunts, uncles, siblings-in-law, half-siblings, cousins, adopted children, step-parents/step-children, and cohabiting partners. The term close relatives is used similarly.

The concept of "immediate family" acknowledges that a person has or may feel particular responsibilities towards family members, which may make it difficult to act fairly towards non-family (hence the refusal of many companies to employ immediate family members of current employees), or which call for special allowance to recognise this responsibility (such as compensation on death, or permission to leave work to attend a funeral). It is used by travel insurance policies to determine a set of people on the basis of whose health someone might need to cancel a journey or return early. The concept is used by some countries' inheritance laws.