| HD 128311 b | |
| Discoverer: | Butler et al. |
| Discovery Site: |  California, United States |
| Discovered: | 2002 |
| Apsis: | astron |
| Aphelion: | 1.412AU |
| Perihelion: | 0.756AU |
| Semimajor: | 1.084± |
| Period: | 453.019± |
| Avg Speed: | 26.2 |
| Star: | HD 128311 |
| Inclination: | >30 |
| Mass: | ≥ |
HD 128311 b is an exoplanet located approximately 54 light-years away in the constellation of Boötes. This planet orbits in an eccentric orbit about 1.084 AU from its star (HD 128311). The planet has a minimum mass of 1.769 Jupiter masses.