In many countries alimony, maintenance, or spousal support is an obligation established by law that is based on the premise that both spouses have an absolute obligation to support each other during the marriage (or civil union) unless they are legally separated, though in some instances the obligation to support may continue after separation. Once dissolution proceedings commence, either party may seek interim or pendente litelitigation.

Where a divorce or dissolution of marriage (civil union) is granted, either party may ask for post-marital alimony. It is not an absolute right, but may be granted, the amount and terms varying with the circumstances. If one party is already receiving support at the time of the divorce, the previous order is not automatically continued (although this can be requested), as the arguments for support during and after the marriage can be different.

Historically, alimony arose as a result of the indissoluable nature of marriage. Because divorce was rare, husband and wife remained married after their physical separation and the husband's obligation to support his wife continued. With the growing view that men and women should be treated equally, the law recognized that both husbands and wives owed each other a similar duty of support. Accordingly, courts now may order either the husband or wife to pay alimony.

Some of the possible factors that bear on the amount and duration of the support are: (see below for more details on these)

• length of the marriage
• time separated while still married
• age of the parties at the time of the divorce
• relative income of the parties
• future financial prospects of the parties
• health of the parties
• fault in marital breakdown

Unless the parties agree on the terms of their divorce in a binding written instrument, the court will make a fair determination based on the legal argument and the testimony submitted by both parties. This can be modified at any future date based on a change of circumstances by either party on proper notice to the other party and application to the court. The courts are generally reluctant to modify an existing agreement unless the reasons are compelling. In some jurisdictions, the court always has jurisdiction to grant maintenance should one of the former spouses become a public charge.