Philip Lader (born March 17, 1946), is a former US Ambassador to the Court of St. James’s and former chairman of WPP plc, the global advertising and communications services firm.

In 1981, he and his wife, Linda LeSourd Lader, founded Renaissance Weekends, the non-partisan retreats that seek to build bridges between innovative leaders from diverse fields.

[1] During his studies at Harvard Law School, Lader was an Assistant Professor of Political Science at Newton College of the Sacred Heart[citation needed].

Upon sale of that company in 1983, he was president of Winthrop University in Rock Hill, South Carolina, which was awarded the National Gold Medal for "general improvement in programs" by the Council for Advancement & Support of Education during his tenure, and served until becoming a candidate in the 1986 South Carolina gubernatorial election, finishing second to then-Lieutenant Governor Michael R. Daniel and foregoing the run-off in support of Daniel, who narrowly lost to Republican Carroll A. Campbell Jr. in the general election.

From 1986 to 1989, Lader was executive vice president of Sir James Goldsmith's U.S. holdings – which included America's then-largest private landholdings, sixth-largest forest products company, largest computer supplies supplier, and oil and gas interests.