Joseph Ridgway Grundy (January 13, 1863 – March 3, 1961) was an American textile manufacturer and Republican Party politician from Bristol, Pennsylvania.

Grundy had a summer home on the Neshaminy Creek called Walnut Grove and one in the city of Bristol Borough.

In his memoir, the economist and social activist Scott Nearing claimed that Grundy, whose textile mills employed workers as young as thirteen, objected to the efforts of activists to restrict child labor by raising the age of full-time legal employment.

Nearing also described Grundy as one of the conservatives whose influence over the Pennsylvania legislature (which was giving subventions to universities in the state) prompted trustees at the University of Pennsylvania to fire Nearing – a professor at the Wharton School of Business – in 1915, leading to what historians have described as one of the first major academic freedom debates in United States during the early twentieth century.

The Bristol Borough home of Senator Grundy, as stated in his will, was left to be preserved as a museum and memorial library named after his only sister, Margaret Ridgway Grundy, in her and their family's honor and is open to the public for touring free of charge.