Greg's published works include:
Books
- "*The Creed of Christendom: Its Foundations and Superstructure" *(1851)*
- "*Enigmas of Life" *(1872)*
- "*Literary and Social Judgments" *(1868 & 1869, two series)*
- "*Mistaken Aims and Attainable Ideals of the Working Classes" *(1876)*
- "*Rocks Ahead: or The Warnings of Cassandra" *(1874)*
- "*Truth versus Edification" *(1869)*
- "*Why are Women Redundant?" *(1869)*
Pamphlets
- "*The Ballot-Box and Social Reform" *(1865)*
- "*Essays on Political and Social Science" *(1853, two series)*
- "*Free Trade and British Manufacturers" *(1849)*
- "*Letters on the Politics of England, France, Germany and Italy" *(1848)*
- "*Practical Suggestions on the Future Government of India" *(1858)*
- "*Why are We at War?" *(1854)*