The Roberts Court is the time since 2005 during which the Supreme Court of the United States has been led by John Roberts as Chief Justice. Roberts succeeded William Rehnquist as Chief Justice after Rehnquist's death. It has been considered to be the most conservative court since the Vinson Court (1946–1953), with landmark rulings falling along partisan lines and very close confirmation votes for most of its members.

The ideology of the Roberts court was shaped early on by the retirement of the relatively moderate Justice Sandra Day O'Connor and the confirmation of the more conservative Justice Samuel Alito in 2006. The ideological balance shifted further rightward through the replacement of swing-vote Anthony Kennedy with Brett Kavanaugh in 2018 and the replacement of liberal Ruth Bader Ginsburg with Amy Coney Barrett in 2020. Some media outlets claim members of the Roberts court themselves are deeply politically polarized.

Roberts was originally nominated by President George W. Bush as an associate justice to succeed Sandra Day O'Connor, who had announced her retirement, effective with the confirmation of her successor. However, before the Senate could act upon the nomination, Chief Justice William Rehnquist died. President Bush quickly withdrew the initial nomination and resubmitted it as a nomination for Chief Justice; this second Roberts nomination was confirmed by the Senate on September 29, 2005, by a 78–22 vote. Roberts took the constitutional oath of office, administered by senior Associate Justice John Paul Stevens (who was the acting chief justice during the vacancy) at the White House after his confirmation the same day. On October 3, Roberts took the judicial oath provided for by the Judiciary Act of 1789, prior to the first oral arguments of the 2005 term. The Roberts Court commenced with Roberts as Chief Justice and the remaining eight associate justices from the Rehnquist Court: Stevens, O'Connor, Antonin Scalia, Anthony Kennedy, David Souter, Clarence Thomas, Ruth Bader Ginsburg, and Stephen Breyer.

President Bush's second nominee to replace O'Connor, Harriet Miers, withdrew before a vote; Bush's third nominee to replace O'Connor was Samuel Alito, who was confirmed in January 2006. In 2009, President Barack Obama nominated Sonia Sotomayor to replace Souter; she was confirmed. In 2010, Obama nominated Elena Kagan to replace Stevens; she, too, was confirmed. In February 2016, Justice Scalia died; in the following month, Obama nominated Merrick Garland, but Garland's nomination was never considered by the Senate, and it expired when the 114th Congress ended and the 115th Congress began on January 3, 2017. On January 31, 2017, President Donald Trump nominated Neil Gorsuch to replace Scalia. Democrats in the Senate filibustered the Gorsuch. After that, Gorsuch was confirmed in April 2017. In 2018, Trump nominated Brett Kavanaugh to replace Kennedy; he was confirmed. In September 2020, Justice Ginsburg died; Trump nominated Amy Coney Barrett to succeed Ginsburg and she was confirmed on October 26, 2020, eight days before the 2020 election. In January 2022, Breyer announced his retirement effective at the end of the Supreme Court term, assuming his successor was confirmed, in a letter to President Joe Biden. Biden nominated Ketanji Brown Jackson to succeed Breyer, and she was confirmed by the Senate three months later. Breyer remained on the Court until it went into its summer recess on June 30, at which point Jackson was sworn in, becoming the first black woman and the first former federal public defender to serve on the Supreme Court.

Note: The blue vertical line denotes "now" (April 2026).

Presidents during this court have been George W. Bush, Barack Obama, Donald Trump (two non-consecutive terms), and Joe Biden. Congresses included the 109th through the current 119th United States Congresses.

The Roberts Court has issued major rulings on incorporation of the Bill of Rights, gun control, affirmative action, campaign finance regulation, election law, abortion, capital punishment, LGBT rights, unlawful search and seizure, and criminal sentencing. Major decisions of the Roberts Court include:

The Roberts Court shifted ideologically further to the right after Donald Trump's first presidency, but was considered conservative from the beginning. Among former justices, Scalia and Kennedy had been more conservative, while Souter, Stevens, Ginsburg, and Breyer had been more liberal. These two blocs of voters had lined up together in several major cases, though Justice Kennedy occasionally sided with the liberal bloc. Roberts' strongest inclination on the Court before Trump had been to attempt to re-establish the centrist aesthetics of the Court as being party neutral, in contrast to his predecessor Rehnquist who had devoted significant effort to promote a 'states-rights' orientation for the Court. The judicial philosophy of Roberts on the Supreme Court before Trump was assessed by leading court commentators including Jeffrey Rosen and Marcia Coyle. The Roberts Court has been described by many as "dominated by an ambitious conservative wing" since Trump's first presidency. Roberts, Thomas, Alito, Gorsuch, Kavanaugh, and Barrett generally have taken more conservative positions, while Sotomayor, Kagan, and Jackson have generally taken more liberal positions. Roberts has also served as a swing vote, often advocating for narrow rulings and compromise among the two blocs of justices. Though the Court sometimes does divide along partisan lines, attorney and SCOTUSblog founder Tom Goldstein has noted that more cases are decided 9–0 and that the individual justices hold a wide array of views. Although Roberts is identified as having a conservative judicial philosophy, his vote in National Federation of Independent Business v. Sebelius (2012) upholding the constitutionality of the Patient Protection and Affordable Care Act (ACA) has caused reflection in the press concerning the comparative standing of his conservative judicial philosophy compared to other sitting justices of conservative orientation; he is seen as having a more moderate conservative orientation, particularly when his vote to uphold the ACA is compared to Rehnquist's vote in Bush v. Gore. Some commentators have also noted that Roberts uses his vote in high-profile cases to achieve a facially-neutral result that sets up for larger conservative rulings in the future. The Five Four Podcast went so far as to deem this maneuver the "Roberts Two-Step." Regarding Roberts' contemporaneous peers on the bench, his judicial philosophy is seen as more moderate and conciliatory than that of Samuel Alito and Clarence Thomas. Roberts has not indicated any particularly enhanced reading of originalism or framer's intentions as has been plainly evident in Scalia's speeches and writings. Roberts' voting pattern is most closely aligned with Brett Kavanaugh's. After Ginsburg was replaced by Barrett, several commentators wrote that Roberts was no longer the leading justice. As the five other conservative justices could outvote the rest, he supposedly could no longer preside over a moderately conservative course while respecting precedent. Some said this view was confirmed by the court's 2022 ruling in Dobbs v. Jackson Women's Health Organization, which overturned the landmark rulings Roe v. Wade and Planned Parenthood v. Casey of 1973 and 1992, respectively. The conservative bloc is sometimes further split into a wing more hesitant to overrule precedent (Roberts, Kavanaugh, and Barrett), and a wing more willing to overrule precedent (Clarence Thomas, Samuel Alito, and Neil Gorsuch). Roberts wrote the majority opinion in West Virginia v. EPA which officially established the major questions doctrine and restricted the ability of the EPA to regulate power plant emissions using generation shifting under the Clean Air Act. That opinion drew ire from critics who argued that Roberts and the conservative bloc manufactured a doctrine to thwart climate reforms.