The Silent Sentinels, also known as the Sentinels of Liberty, were an American group of over 2,000 women in favor of women's suffrage organized by Alice Paul and the National Woman's Party, who nonviolently protested in front of the White House during Woodrow Wilson's presidency starting on January 10, 1917. Nearly 500 were arrested, and 168 served jail time. They were the first group to picket the White House. Later, they also protested in Lafayette Square, not stopping until June 4, 1919 when the Nineteenth Amendment to the United States Constitution was passed both by the House of Representatives and the Senate.

The Sentinels started their protest after a meeting with the president on January 9, 1917, during which he told the women to "concert public opinion on behalf of women's suffrage." The protesters served as a constant reminder to Wilson of his lack of support for suffrage. At first the picketers were tolerated, but they were later arrested on charges of obstructing traffic.

The name Silent Sentinels was given to the women because of their silent protesting, and had been coined by Harriot Stanton Blatch. Using silence as a form of protest was a new principled, strategic, and rhetorical strategy within the national suffrage movement and within their own assortment of protest strategies. Throughout this two and a half year long vigil, many of the women who picketed were harassed, arrested, and unjustly treated by local and US authorities, including the torture and abuse inflicted on them before and during the November 14, 1917 Night of Terror.

The Silent Sentinels' protests were organized by the National Woman's Party (NWP), a militant women's suffrage organization. The NWP was first founded as the Congressional Union for Woman Suffrage (CUWS) in 1913 by Alice Paul and Lucy Burns following their organizing of NAWSA's woman suffrage parade in Washington DC in March 1913. CUWS by definition was an organization that took a militant approach to women's suffrage and broke away from the more moderate National American Woman Suffrage Association (NAWSA). CUWS only lasted for three years until its founders merged it with the Woman's Party to form the National Woman's Party. The National Woman's Party boasted fewer members than National American Woman Suffrage Association (having 50,000 members to NAWSA's million), but its tactics were more attention-grabbing and harnessed more media coverage. The NWP's members are known primarily for picketing the White House and going on hunger strikes while in the jail or workhouse.

The Suffragist was the National Woman's Party weekly newsletter. The Suffragist acted as a voice for the Silent Sentinels throughout their vigil. It covered the Sentinels' progress and included interviews with protesters, reports on President Woodrow Wilson's (non) reaction, and political essays. While the Sentinels were in prison, a few members wrote about their experiences which were later posted in The Suffragist. "Although The Suffragist was intended for mass circulation, its subscription peaked at just over 20,000 issues in 1917. Most copies went to party members, advertisers, branch headquarters, and NWP organizers, which strongly suggests that the suffragists themselves were a key audience of the publication."

The following are examples of banners held by the women:

The Sentinels all wore purple, white, and gold sashes which were the NWP's colors. Their banners were also usually colored this way.

The public's responses to the Silent Sentinels were varied.