Catharine Gouger Waugh McCulloch (June 4, 1862 – April 20, 1945) was an American lawyer, suffragist, and reformer. She actively lobbied for women's suffrage at the local, state, and national levels as a leader in the Illinois Equal Suffrage Association, Chicago Political Equality League, and National American Woman Suffrage Association. She was the first woman elected Justice of the Peace in Illinois.

Catharine Waugh was born in New York to Susan Gouger and Abraham Miller Waugh. She was of French and Irish ancestry. Raised in Illinois, she graduated from Rockford Female Seminary in 1882, where she wrote a thesis on women's wages and earned both a B.A. and M.A. degree. Waugh then attended Chicago's Union College of Law (now Northwestern Pritzker School of Law). After graduating and passing the bar in 1886, Waugh sought employment in Chicago but faced gender discrimination. She returned to Rockford, Illinois and started her own practice.

In 1890, Catharine Waugh married her former law school classmate, Frank Hathorn McCulloch. They moved to Chicago and merged practices to form the law firm of McCulloch and McCulloch. Catharine sought equality in her relationship as both a private and political arrangement. According to letters she sent to colleagues, she believed her marriage to McCulloch helped advance her career. She raised four children: Hugh Waugh, Hathorn Waugh, Catharine Waugh, and Frank Waugh.

McCulloch was a member of the Equity Club, a correspondence network founded in 1887 to provide support, friendship, and advice among women lawyers across the country. In 1888, McCulloch unsuccessfully ran for state's attorney on the Prohibition party ticket.

McCulloch began serving as the legislative chair of the Illinois Equal Suffrage Association in 1890. After the Illinois Supreme Court upheld a law granting women the right to vote in school district elections in 1891, McCulloch worked on a bill that would ensure women's suffrage for local and presidential elections in the state of Illinois. McCulloch and her colleagues at the Illinois Equal Suffrage Association actively lobbied for the bill from 1893 to 1913, even organizing train and automobile tours to rally suffrage supporters across the state. McCulloch's public-oriented methods of mobilizing supporters through rallies and publications reflected the style of many clubwomen, settlement-house workers, and other Progressive Era activists who sought suffrage as a means to advance other reform efforts. Her approach contrasted with that of more conservative members of the Illinois Equal Suffrage Association like Grace Wilbur Trout, who preferred more quiet and diplomatic lobbying.

In 1894, McCulloch and fellow members of the Chicago Woman's Club founded the Chicago Political Equity League to campaign for municipal suffrage. In addition to her suffrage work, McCulloch advocated for maternalist reform measures. For example, she championed the passage of a law in 1901 that gave women equal guardianship with their husbands over their children. In 1905, she helped raise the age of consent for girls from 14 to 16 years.

McCulloch was elected Justice of the Peace in Evanston, Illinois in 1907 (and re-elected in 1909), trouncing her male competitor and making McCulloch the first woman elected to that office in Illinois. In an attempt to challenge McCulloch's position, the attorney for McCulloch's male opponent claimed that women were ineligible to hold all constitutional offices in the state because they were not eligible voters. However, Illinois's state attorney general advised the governor to grant McCulloch's commission, leaving her competitor the option to pursue the constitutional objection in court. Instead of challenging the eligibility of her commission in court, McCulloch's male competitor tried to best her in the next election, losing yet again.

While a Justice of the Peace, McCulloch made national headlines by agreeing to conduct egalitarian marriage ceremonies in which she omitted the word "obey" from the ritualized words the woman was supposed to say; at that time, the man pledged to "love, honor and cherish" while the woman pledged to "love, honor and obey."