Pleasantville is a village in the town of Mount Pleasant, in Westchester County, New York, United States. It is located 30 miles north of Manhattan. The village population was 7,513 at the 2020 census. Pleasantville is home to the secondary campus of Pace University and to the Jacob Burns Film Center. Most of Pleasantville is served by the Pleasantville Union Free School District, with small parts of northern Pleasantville served by the Chappaqua Central School District. The village is also home to the Bedford Road School, Pleasantville Middle School, and Pleasantville High School. The region of Pleasantville commonly referred to as "The Flats" is mostly served by the Mount Pleasant Central School district.

The settlement of Pleasantville dates back to the Rechgawawank and Sinsink tribes, belonging to the Munsee dialect of the Lenni Lenape. This region of the Hudson Valley has been inhabited since just after the last ice age. Lenape communities practiced ecosystem management, small-scale agriculture, hunting and gathering, democratic politics, and matrilineal governance. Called the "Grandfathers" by neighboring tribes, the Lenape were peaceful and skilled at conflict resolution between tribes and established trading routes crossing through the present-day village before the arrival of Europeans. By the end of the 17th century, most if not all of the New York Lenape people had been killed by disease or conflict or had been displaced westward; Lenape in the 21st century reside in Ontario, Oklahoma, Ohio, Wisconsin, New Jersey, and Pennsylvania. French Huguenot Isaac See settled here as an agent for Dutch landowner Frederick Philipse in 1695, beginning the modern settler-colonial history of Pleasantville.

By the time of the American Revolution, the population of the growing settlement comprised English, Dutch, and Quakers, most of whom were tenant farmers. During the Revolution, this area was part of the Neutral Ground, where there were conflicting loyalties among the settlers. British spy Major John André passed through present-day Pleasantville carrying information from Benedict Arnold at Fort Clinton (West Point) to the British in New York City. André lost his bearings near the present-day corner of Bedford Road and Choate Lane and was captured in Tarrytown, New York. The capture of André is often cited as a key factor in the ultimate victory of the American forces.

As the area's population grew in the early 19th century, the settlement was called Clark's Corners, referring to property owned by Henry Clark at the intersection of Broadway and Bedford Road. This area was the village's original commercial center. In the 1820s, the newly appointed postmaster, Henry Romer, was directed by the Postmaster General's office in Washington, D.C., to give a name to the post office planned here. Romer's proposed name, Clarksville, was rejected because another New York post office already had the name. His second choice, Pleasantville, was accepted, and the Pleasantville Post Office opened on February 29, 1828.

A significant change in the development of Pleasantville came with the arrival of the New York Central Railroad and New York and Harlem Railroad in 1846. In the following year, a train station was built near the present corner of Bedford Road and Wheeler Avenue, and as a result the commercial center of Pleasantville shifted to its current location. The older business district at Bedford Road and Broadway is today called the Old Village. The railroad offered a speedier and more frequent connection with New York City—only 70 minutes away by rail, compared with a five-hour overland journey by stagecoach or a two-hour steamboat trip down the Hudson River. The present-day train station, which currently houses a restaurant, was built in 1905 and was moved to its present location in the 1950s to accommodate the lowering of the tracks below grade. Before the addition of the now heavily trafficked station, commuters working in New York City and lower Westchester County were forced to rely on rides from Marc Damon, now famous in Pleasantville for being "The Friendly Coachman".

According to several sources, Pleasantville was a stop on the Underground Railroad, a network of safe houses for escaped slaves from the South on their way to freedom in the north.

The latter half of the 19th century was a time of rapid growth in Pleasantville. By the 1870s, there were four shoemaking businesses, a shirtmaking business, and a pickle factory. The first newspaper to serve the village, The Pleasantville Pioneer, was launched in about 1886. The village's numerous small farms and orchards began to be subdivided for a wave of solid foursquare and Victorian houses built for a growing middle class. The 1890s saw the establishment of a police department, volunteer fire department, and a library system. Pleasantville was incorporated as a village on March 16, 1897.

In the following years, Pleasantville quickly developed into a modern suburb of New York, with a large number of workers commuting between the village and the metropolis on what is now the Metro-North Railroad's Harlem Line. During the first two decades of the 20th century, roads were paved for the first time, water mains were installed, and electrical wires brought power to the village's houses. Other improvements during the first half of the 20th century include the construction of Soldiers and Sailors Field in 1909, the Saw Mill River Parkway in 1924, the Rome Theater in 1925, Memorial Plaza in 1930, Parkway Field in 1930, and Nannahagen Park in 1937 (the adjacent village pool was completed two years later). By the time of World War II, the village had taken on the appearance that it bears today.