| ALGOL X | ⊕ 1964 | ↓ ↑ ⊕ Numerical Scientific | ⊕ True ALGOL60s | ⊕ Germany | Algol 60 revision proposal |
| Constraint Algol | ⊕ 1964 | ↓ ↑ ⊕ Numerical Scientific | ⊕ True ALGOL60s | ⊕ United States | Algol 60 with constraints |
| Extended ALGOL | ⊕ 1964 | ↓ ↑ ⊕ Numerical Scientific | ⊕ True ALGOL60s | ⊕ United States | |
| IFIP ALGOL | ⊕ 1964 | ↓ ↑ ⊕ Numerical Scientific | ⊕ True ALGOL60s | ⊕ International | |
| VALGOL II | ⊕ 1964 | ↓ ↑ ⊕ Numerical Scientific | ⊕ True ALGOL60s | ⊕ United States | |
| Whetstone Algol | ⊕ 1964 | ↓ ↑ ⊕ Numerical Scientific | ⊕ True ALGOL60s | ⊕ United Kingdom |