Electoral fraud is illegal interference with the process of an election. Acts of fraud tend to involve affecting vote counts to bring about a desired election outcome, whether by increasing the vote share of the favored candidate, depressing the vote share of the rival candidates, or both.

Election fraud is probably as old as elections themselves. The first suspicion dates back to 471 BC in the Athenian democracy. Archaeologists found 190 pieces of broken pottery used then as ballots with only 14 different handwritings.

Electoral fraud is illegal in most countries including dictatorships likely to both control the electoral process and excuse any measures that achieve a desired result.

Especially with national elections, successful election fraud can have the effect of a coup d'état or corruption of the democracy. But even if it does not go this far, the 500 million dollar campaigning during the United States general elections, 2006 shows how much might be at stake in some countries.

A look at some narrow elections with a margin of less than 0.1% shows that sometimes there would not be much fraud needed to change the outcome.

Extreme examples of election fraud are sham elections that are a common event in dictatorial regimes that still feel the need to establish some element of public legitimacy, some even showing 100% of eligible voters voting on behalf of the régime. Most people only call a regime democratic as long as electoral fraud is rare, isolated, and small, or that electoral fraud by opposing groups roughly cancels the effects.

Electoral fraud is not limited to political polls and can happen in any kind of election where the potential gain is worth the risk for the cheater, as in elections for labor union officials, student councils, sports judging, and the awarding of merit to books, films, music, or television programming.