| Acronym | Meaning |
| GPO | Geophysical Prove-Out (US Army Corps of Engineers) |
| GPO | Government Pension Offset |
| GPO | Government Printing Office |
| GPO | Government Project Officer |
| GPO | Government Publications Office |
| GPO | Ground-Based FEL Project Office |
| GPO | Gun Plot Officer |
| GPO | Gun Position Officer |