[13] Williams won his third term in the House on November 8, when Donald Trump carried the electoral vote majority over Hillary Rodham Clinton.

[16] In 2015, Williams condemned the Supreme Court's decision in Obergefell v. Hodges, which held that same-sex marriage bans violated the constitution.

[17] Williams supported Trump's 2017 executive order imposing a ban on entry to the U.S. to citizens of seven Muslim-majority countries, calling it a "commonsense" measure and saying that opponents "are lost in the political correctness of this.

[20] The legislation was spurred by the deaths of Raechel and Jacqueline Houck,[21] who were killed in 2004 while driving a rented, recalled vehicle that caught fire and crashed into a semi.

[22] The investigation's focus was a provision Williams authored that would have exempted dealerships like his and allowed renting vehicles under active safety recall.

[23][24] The independent nonpartisan Office of Congressional Ethics found that Williams violated House ethics rules, noting that he refused to cooperate; by unanimous, bipartisan vote the OCE found that "there is substantial reason to believe that Rep. Williams' personal financial interest in his auto dealership may be perceived as having influenced his performance of official duties—namely, his decision to offer an amendment to the surface transportation legislation".

[25] The House Ethics committee determined that the amendment "could have affected Representative Williams' personal financial interests" but decided to end the investigation and took no further action.

[35][36][37][38] In December 2020, Williams was one of 126 Republican members of the House of Representatives to sign an amicus brief in support of Texas v. Pennsylvania, a lawsuit filed at the United States Supreme Court contesting the results of the 2020 presidential election, in which Joe Biden defeated Trump.

[39] The Supreme Court declined to hear the case on the basis that Texas lacked standing under Article III of the Constitution to challenge the results of an election held by another state.

[40][41][42] In September 2021, nonprofit group Campaign Legal Center filed an ethics complaint against Williams with the Office of Congressional Ethics, claiming that Williams appeared to have violated the Stop Trading on Congressional Knowledge (STOCK) Act of 2012, a federal transparency and conflict-of-interest law, by failing to properly disclose sales of stock in General Electric, Nvidia, and The Walt Disney Co. worth between $3,003 and $45,000 made by his wife in 2019.

[46] Williams is a trustee of TCU and the George Bush School of Government and Public Service at Texas A&M University in College Station.