Honorary Membership was limited to 10 from 1890-1900, and to 15 from 1901 onwards. Corresponding Membership was a lesser class of Honoris causa membership in the early years. A few honorary members, such as Barnard, were first made corresponding members for a short time before being recommissioned as honorary members.
| Nation(s) | Start | End | |
|---|---|---|---|
| Hertzsprung, Prof. Ejnar | Denmark | 1946 | 1967 |
| Hirayama, Prof. Kiyotsugu | Japan | 1907 | 1943 |
| Hogg, Dr. Helen S. | Canada | 1987 | 1993 |
| Holden, Dr. Edward S. | USA | 1891 | 1914 |
| Hubble, Dr. Edwin Powell | USA | 1951 | 1953 |
| Huggins, Dr. Sir William | United Kingdom | 1891 | 1910 |
| Hunter, Mr. Andrew F. | Canada | 1890 | 1891 |
| Iwanowska, Dr. Wilhelmina | Poland | 1973 | 1999 |
| Joy, Dr. Alfred H. | USA | 1961 | 1973 |
| Kedzie, Mr. John Hume | USA | 1890 | 1903 |