Proxy voting is a form of voting whereby a member of a decision-making body may delegate their voting power to a representative, to enable a vote in absence. The representative may be another member of the same body, or external. A person so designated is called a "proxy" and the person designating them is called a "principal". Proxy appointments can be used to form a voting bloc that can exercise greater influence in deliberations or negotiations. Proxy voting is a particularly important practice with respect to corporations; in the United States, investment advisers often vote proxies on behalf of their client accounts.

A related topic is liquid democracy, a family of electoral systems where votes are transferable and grouped by voters, candidates or combination of both to create proportional representation, and delegated democracy.

Another related topic is the so-called Proxy Plan, or interactive representation electoral system whereby elected representatives would wield as many votes as they received in the previous election. Oregon held a referendum on adopting such an electoral system in 1912.

The United States parliamentary manual Riddick's Rules of Procedure notes that, under proxy voting, voting for officers should be done by ballot, due to the difficulties involved in authentication if a member simply calls out, "I cast 17 votes for Mr. X."

Proxy voting is also an important feature in corporate governance in the United States through the proxy statement. Companies use proxy solicitation agencies to secure proxy votes.

The rules of some assemblies presently forbid proxy voting. There is a plan to forbid proxy voting in the United States House of Representatives. A recent vote showed 53 Democrats and 26 Republicans voted by proxy. Forbidding proxy voting can result, however, in the absence of a quorum and the need to compel attendance by a sufficient number of missing members to get a quorum. See call of the house.

It is possible for automatic proxy voting to be used in legislatures, by way of direct representation (this idea is essentially a form of weighted voting). For example, it has been proposed that instead of electing members from single-member districts (that may have been gerrymandered), members be elected at large, but when seated each member cast the number of votes he or she received in the last election. Thus, if, for example, a state were allocated 32 members in the U.S. House of Representatives, the 32 candidates who received the most votes in the at-large election would be seated, but each would cast a different number of votes on the floor and in committee. This proposal would allow for representation of minority views in legislative deliberations, as it does in deliberations at shareholder meetings of corporations. Such a concept was proposed in a submission to the 2007 Ontario Citizens' Assembly process.

Another example is Evaluative Proportional Representation (EPR). It elects all the members of a legislative body. Each citizen grades the fitness for office of as many of the candidates as they wish as either Excellent (ideal), Very Good, Good, Acceptable, Poor, or Reject. Multiple candidates may be given the same grade by a voter. Each citizen elects their representative at-large for a city council. For a large and diverse state legislature, each citizen chooses to vote through any of the districts or official electoral associations in the country. Each grades any number of candidates in the whole country. Each elected representative has a different voting power (a different number of weighted votes) in the legislative body. This number is equal to the total number of highest available grades counted for them from all the voters – no citizen's vote is "wasted". Each voter is represented equally.