An Assurance of Support (AoS) is an agreement by the sponsor or another eligible person to repay certain social security payments made by the Australian Government to the person or their family members who are migrating to Australia during their AoS period. The relevant social security payments include Special Benefit, Newstart Allowance, Widow Allowance, Mature Age Allowance, Parenting Payment (Partnered), Partner Allowance, Youth Allowance, Austudy Payment, and Crisis Payment. The assurer also commits to providing financial support to the person applying to migrate to Australia, so they do not have to rely on social security payments. The AoS period is 10 years for contributory parent visa applicants and two years for all other visas. The AoS period starts when the visa is granted for applicants in Australia and when the visa holder arrives in Australia for applicants outside Australia.

Certain permanent visas under the family stream require a mandatory AoS, including the payment of a financial bond. The visa categories that require a mandatory AoS are Parent, Aged Parent, Contributory Parent, Contributory Aged Parent, Aged Dependent Relative, and Remaining Relative. Applicants aged 18 years and above require a bond, but all applicants must have an AoS.

For a permanent Contributory Parent or Contributory Aged Parent visa, the main applicant requires a bond of AUD $10,000, which is held for 10 years. Secondary adult applicants require a bond of AUD $4,000. For a permanent Parent, Aged Parent, Aged Dependent Relative, or Remaining Relative visa, the main applicant requires a bond of AUD $5,000, held for two years. Secondary adult applicants require a bond of AUD $2,000. If the assurer is an organisation, a financial bond of AUD $10,000 for each application is required.