| State | Sierra Leone |
| Treaty | Outer Space Treaty |
| Action Type | Ratification |
| Depositary | Government of the United States of America |
| Date | 14 July 1967 |
| Other Actions | Ratification on deposit with London — 25 October 1967 Signature on deposit with London — 27 January 1967 Ratification on deposit with Moscow — 13 July 1967 Signature on deposit with Moscow — 27 January 1967 Signature on deposit with Washington — 16 May 1967 |