information:filtering, structural:summarization
21st century

The museum's lecture hall was renamed the Samuel J. and Ethel LeFrak Theater in 2001 after Samuel J. LeFrak donated $8 million to the AMNH. The museum's south facade, spanning 77th Street from Central Park West to Columbus Avenue, was cleaned, repaired, and re-emerged in 2009. Steven Reichl, a spokesman for the museum, said that work would include restoring 650 black-cherry window frames and stone repairs. The museum's consultant on the latest renovation was Wiss, Janney, Elstner Associates, Inc., an architectural and engineering firm with headquarters in Northbrook, Illinois. The museum also restored the mural in Roosevelt Memorial Hall in 2010.

In 2014, the museum published plans for a $325 million, 195,000 sq ft (18,100 m) annex, the Richard Gilder Center for Science, Education, and Innovation, on the Columbus Avenue side. On October 11, 2016, the Landmarks Preservation Commission unanimously approved the expansion. Construction of the Gilder Center, which was expected to break ground the next year following design development and Environmental Impact Statement stages, would entail demolition of three museum buildings built between 1874 and 1935. The museum filed plans for the expansion in August 2017, but due to community opposition, construction did not start until June 2019.

The Gilder Center opened on May 4, 2023, and the museum saw 1.5 million visitors over the next three months. In late 2023, the museum announced that it would stop displaying human remains from its collection. Despite the 1990 passage of the Native American Graves Protection and Repatriation Act (NAGPRA), as late as 2023, the AMNH held an estimated 1,900 Native American remains that had not been repatriated. After the act was revised in January 2024, the AMNH's Eastern Woodlands and Great Plains halls were closed because the museum would have needed permission to display all of the artifacts in the halls. The museum agreed to repatriate the remains that July.