Life insurance is a contract between an insurance policy holder and an insurer or assurer, where the insurer promises to pay a designated beneficiary a sum of money upon the death of an insured person (often the policy holder). Depending on the contract, other events such as terminal illness or critical illness can also trigger payment. The policy holder typically pays a premium, either regularly or as one lump sum. The benefits may include other expenses, such as funeral expenses.

Life policies are legal contracts and the terms of each contract describe the limitations of the insured events. Often, specific exclusions written into the contract limit the liability of the insurer; common examples include claims relating to suicide, fraud, war, riot, and civil commotion. Difficulties may arise where an event is not clearly defined, for example: the insured knowingly incurred a risk by consenting to an experimental medical procedure or by taking medication resulting in injury or death.

Modern life insurance bears some similarity to the asset-management industry, and life insurers have diversified their product offerings into retirement products such as annuities.

Life-based contracts tend to fall into two major categories:

Protection policies: designed to provide a benefit, typically a lump-sum payment, in the event of a specified occurrence. A common form (more common in years past) of a protection-policy design is term insurance.
Investment policies: the main objective of these policies is to facilitate the growth of capital by regular or single premiums. Common forms (in the United States) are whole life, universal life, and variable life policies.