Ronald N. Weiser (born July 7, 1945) is an American businessman, philanthropist, diplomat, and political fundraiser.

A major donor and financier for the Republican Party, Weiser played key fundraising roles in the presidential campaigns of George W. Bush, John McCain, and Donald Trump.

[12] The relationship between Weiser's ownership of an Ann Arbor real-estate company, and his roles on the Board of Regents and as a major donor, became controversial during arguments over whether to re-open the university during the COVID-19 pandemic.

[23] Weiser played a key role in the passage of "right-to-work law" legislation enacted by the Michigan Legislature.

[6] In a 2019 editorial, the Detroit News credited Weiser as the architect of "a campaign strategy and a fundraising machine that paved the way for a series of Republican victories" in Michigan, allowing the Republicans to hold complete control of the state government for eight years, even though the state usually leans Democratic.

The only way you can change the leadership is to get out and vote.”[28] After the remarks were publicized, causing an uproar, Weiser said, "I apologize to those I offended for the flippant analogy about three women who are elected officials and for the off-hand comments about two other leaders.

"[29] He claimed that he had never advocated for violence and added, "While I will always fight for the people and policies I believe in, I pledge to be part of a respectful political dialogue going forward.

"[29] University of Michigan Board of Regents chair Denise Ilitch introduced a resolution condemning Weiser's statement and called him to resign from the board; the resolution passed 5–0 at the April 2, 2021 meeting, with Weiser and Sarah Hubbard abstaining, and one regent absent.

"[30] Weiser, however, refused to resign, saying, "I regret my poorly chosen words that were offhand remarks made at a private Republican Party meeting" but "I will not be cancelled.

Weiser’s efforts followed the previous year’s controversial presidential election (in which there was no evidence of widespread voter fraud).