A bipartisan bill is a political act in which both of the two major political parties agree about all or many parts of a political choice. In a two-party system, like in the United States, bipartisan typically refers to any bill, act, resolution, or any other action of a political body in which both of the major political parties, Republicans and Democrats, are in agreement. Often, compromises are called bipartisan if they reconcile the desires of both parties from an original version of legislation or other proposal. Bipartisanship involves trying to find common ground, but there is debate whether the issues needing common ground are peripheral or central ones.

Bipartisan bills are important in a two-party system because failure to attain bipartisan support can easily lead to legislative gridlock, with each side angering the other, their constituencies, and the general public. Bipartisanship is a phenomenon belonging to a two-party system such as the political system of the United States and does not apply to a parliamentary system since the minority party is not involved in helping write legislation or voting for it.

Examples of bipartisan bills include the Bipartisan Infrastructure Deal, which was passed by Congress in 2021 and is a once-in-a-generation investment in the United States infrastructure and competitiveness. Another example is the Bipartisan Bill to Keep the Government Open, which was passed by Congress in 2023 and ensured that active-duty troops continued to get paid, travelers were spared airport delays, and millions of women and children continued to have access to vital nutrition assistance, among other things.