Richard B. Alley (born 1957) is an American geologist and Evan Pugh Professor of Geosciences at the Pennsylvania State University. He has authored more than 170 refereed scientific publications about the relationships between Earth's cryosphere and global climate change, and is recognized by the Institute for Scientific Information as a "highly cited researcher."

In 1999, Alley was invited to testify about climate change by Vice President Al Gore, in 2003 by the U.S. Senate Committee on Commerce, Science, and Transportation, and again before the U.S. House Committee on Science and Technology in 2007.

Alley's most recent testimony was due to his current role as a lead author of "Chapter 4: Observations: Changes in Snow, Ice and Frozen Ground" for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. He has participated in the joint UN/WMO panel since 1992, having been a contributing author to both the second and third IPCC assessment reports.