政治献金系指对从事竞选活动或其他政治相关活动之个人或团体，无偿提供之动产或不动产、不相当对价之给付、债务之免除或其他经济利益。但党费、会费或义工之服务不包括在内。政治献金是维系民主的必然现象，也是民主社会的政治参与的人权精神，确保政治活动公平及公正，健全民主政治发展，清廉的政治人物也必须直接或间接利用政治献金来选举；许多国家有法令来判断政治献金是否为贿赂，大体而言，没有对价关系叫政治献金、有对价关系而造成官商勾结或利益输送叫贿赂，尤其是财团给的政治献金更需公平且明确的规范，但是2014年4月2日，美国最高法院判决限制选举政治献金的合计金额违反了美国宪法第一修正案，也就是日后美国的选举政治献金金额将无上限。

Campaign finance refers to all funds raised in order to promote candidates, political parties, or policies in elections, referendums, initiatives, party activities, and party organizations. The funds could also detract from the opponents of the above. Campaign funds is the subject heading under which all books dealing with money in politics are catalogued by the Library of Congress. Other nations use other terms for the subject and offer a broader perspective. Cross-national comparisons prefer the more comprehensive "political finance", researchers in continental Europe use "party finance". All of them deal with "the costs of democracy", a term coined by G. Alexander Heard for his famous analysis of campaign finance in the U.S.