| d-Prolog | ⊕ 1988 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ United States | Defeasible Prolog |
| lambda-Prolog | ⊕ 1988 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ United States | |
| NU-Prolog | ⊕ 1988 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Australia | |
| PMS-Prolog | ⊕ 1988 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Australia | |
| PNU-Prolog | ⊕ 1988 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Australia | Parallel Nu-Prolog |
| Prolog/V | ⊕ 1988 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ International | Prolog implemented in Smalltalk |
| SCOOP | ⊕ 1988 | ↓ ↑ ⊕ Specialised Languages | ⊕ Horn clause | ⊕ France | |
| Temporal Prolog | ⊕ 1988 | ↓ ↑ ⊕ String and List Processing | ⊕ Horn clause | ⊕ Hungary |