Wharton's writings on international law include:
- A Digest of the International Law of the United States (3 volumes, 1887)
- The Collected Diplomatic Correspondence of the United States from 1783 to 1789 (6 volumes, 1889)
- International Law Digest (10 volumes, 1886-1906)
- A Treatise on the Conflict of Laws (3rd edition, 1905)
- The Law of Nations (2 volumes, 1897)
In addition to his work on international law, Wharton also wrote several books on other topics, including:
- Social Law, the Genesis and Foundations of Law as a Study (1879)
- The Wharton School Alumni: A Biographical History of the Wharton School of the University of Pennsylvania (1895)
- Legal Maxims (1897)
- Plain Talks on Law (1901)
- American Constitutional History, 1783–1850 (1902)
- Criminal Procedure (11th edition, 1918)