| Classification | Description | Notes |
| Grade 1 | 0 – 25% subluxation | |
| Grade 2 | 25 – 50 % subluxation | |
| Grade 3 | 50 – 75% subluxation | |
| Grade 4 | >75% subluxation |
Reference:
Meyerding, H. W. (1956). “Spondylolisthesis; surgical fusion of lumbosacral portion of spinal column and interarticular facets; use of autogenous bone grafts for relief of disabling backache.” J Int Coll Surg 26(5 Part 1): 566-591.