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.

The person responsible for making payments for a policy is the policy owner, while the insured is the person whose death will trigger payment of the death benefit. The owner and insured may or may not be the same person. For example, if Joe buys a policy on his own life, he is both the owner and the insured. But if Jane, his wife, buys a policy on Joe's life, she is the owner and he is the insured. The policy owner is the guarantor and they will be the person to pay for the policy. The insured is a participant in the contract, but not necessarily a party to it.