AP Poll
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For the 1968 season, the AP Poll returned to ranking 20 teams per week, after ranking only 10 per week from 1961 to 1967. This was also the second time (first since 1965) that the final AP Poll was conducted in January after the completion of bowl season, rather than at the end of the regular season. The final poll would continue to be conducted after bowl season from this season forward.
| Preseason Aug | Week 1 Sep 16 | Week 2 Sep 23 | Week 3 Sep 30 | Week 4 Oct 7 | Week 5 Oct 14 | Week 6 Oct 21 | Week 7 Oct 28 | Week 8 Nov 4 | Week 9 Nov 11 | Week 10 Nov 18 | Week 11 Nov 25 | Week 12 Dec 2 | Week 13 (Final) Jan | ||
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| 1. | Purdue (14) | Purdue (0–0) (14) | Purdue (1–0) (25) | Purdue (2–0) (42) | Purdue (3–0) (35) | USC (4–0) (23) | USC (5–0) (21) | USC (5–0) (24) | USC (6–0) (19) | USC (7–0) (32) | USC (8–0) (27) | Ohio State (9–0) (21.5) | Ohio State (9–0) (34) | Ohio State (10–0) (44) | 1. |
| 2. | USC (10) | USC (0–0) (8) | Notre Dame (1–0) (19) | USC (2–0) (2) | USC (3–0) (1) | Ohio State (3–0) (12) | Ohio State (4–0) (15) | Ohio State (5–0) (12) | Ohio State (6–0) (14) | Ohio State (7–0) (14) | Ohio State (8–0) (7) | USC (9–0) (24.5) | USC (9–0–1) (2) | Penn State (11–0) (2) | 2. |
| 3. | Notre Dame (3) | Notre Dame (0–0) (2) | USC (1–0) (4) | Penn State (2–0) (1) | Penn State (3–0) (1) | Penn State (4–0) (3) | Kansas (5–0) (5) | Kansas (6–0) (6) | Kansas (7–0) (10) | Penn State (7–0) (1) | Penn State (8–0) (2) | Penn State (9–0) (3) | Penn State (9–0) (3) | Texas (9–1–1) (2) | 3. |
| 4. | Oklahoma | Texas (0–0) (2) | Penn State (1–0) (1) | Florida (2–0) | Ohio State (2–0) | Kansas (4–0) (4) | Penn State (4–0) (1) | Penn State (5–0) (1) | Penn State (6–0) (1) | Michigan (7–1) | Michigan (8–1) | Georgia (7–0–2) (1) | Georgia (8–0–2) | USC (9–1–1) | 4. |
| 5. | Texas (3) | Oklahoma (0–0) | Florida (1–0) | Notre Dame (1–1) | Notre Dame (2–1) | Purdue (3–1) | Notre Dame (4–1) | Tennessee (4–0–1) | Tennessee (5–0–1) (1) | Georgia (6–0–2) | Georgia (7–0–2) (1) | Kansas (9–1) | Texas (8–1–1) | Notre Dame (7–2–1) | 5. |
| 6. | Oregon State (2) | Florida (0–0) | Texas (0–0–1) | Ohio State (1–0) | Kansas (3–0) | Notre Dame (3–1) | Tennessee (4–0–1) | Purdue (5–1) | Purdue (6–1) | Missouri (7–1) | Texas (7–1–1) | Texas (7–1–1) | Kansas (9–1) | Arkansas (10–1) (1) | 6. |
| 7. | Florida (1) | Alabama (0–0) (2) | Alabama (1–0) | Nebraska (3–0) | Florida (3–0) | Florida (4–0) | Purdue (4–1) | Georgia (5–0–1) | Michigan (6–1) | Kansas (7–1) | Kansas (8–1) | Tennessee (7–1–1) | Notre Dame (7–2–1) | Kansas (9–2) | 7. |
| 8. | Penn State | Oregon State (0–0) | UCLA (1–0) | Kansas (2–0) | LSU (3–0) | Tennessee (3–0–1) | Georgia (4–0–1) | California (5–1) | Missouri (6–1) | Texas (6–1–1) | Tennessee (6–1–1) | Arkansas (9–1) | Tennessee (8–1–1) | Georgia (8–1–2) | 8. |
| 9. | Tennessee | Ohio State (0–0) | Nebraska (2–0) | UCLA (2–0) | Nebraska (3–0) | Arkansas (4–0) | Miami (FL) (4–1) | Michigan (5–1) | Georgia (5–0–2) | Notre Dame (6–2) | Arkansas (8–1) | Notre Dame (7–2) | Arkansas (9–1) | Missouri (8–3) | 9. |
| 10. | Alabama | Penn State (0–0) | Houston (1–0–1) | LSU (2–0) | Tennessee (2–0–1) | Georgia (3–0–1) | Syracuse (3–1) | Missouri (5–1) | Texas (5–1–1) | Arkansas (7–1) | Notre Dame (7–2) | Houston (6–1–2) | Oklahoma (7–3) | Purdue (8–2) | 10. |
| 11. | Ohio State | Houston (1–0) | Ohio State (0–0) | Alabama (2–0) | Houston (2–0–1) | Syracuse (3–1) | California (4–1) | Texas (4–1–1) | California (5–1–1) | Tennessee (5–1–1) | Houston (5–1–2) | Oklahoma (6–3) | Purdue (8–2) | Oklahoma (7–4) | 11. |
| 12. | Texas A&M | Tennessee (0–0–1) | Kansas (1–0) | Houston (1–0–1) | Michigan State (3–0) | Miami (FL) (3–1) | Michigan (4–1) | Notre Dame (4–2) | Notre Dame (5–2) | Auburn (6–2) | Purdue (7–2) | Purdue (8–2) | Alabama (8–2) | Michigan (8–2) | 12. |
| 13. | Indiana | Texas A&M (0–0) | Indiana (1–0) | Miami (FL) (2–0) | Ole Miss (3–0) | Nebraska (3–1) | Texas (3–1–1) | SMU (5–1) | Houston (3–1–2) | Oregon State (6–2) | Missouri (7–2) | Michigan (8–2) | Michigan (8–2) | Tennessee (8–2–1) | 13. |
| 14. | Nebraska | Nebraska (1–0) | LSU (1–0) | Arizona State (2–0) | Arkansas (3–0) | Stanford (3–1) | Missouri (4–1) | LSU (5–1) | Arkansas (6–1) | Houston (4–1–2) | Oklahoma (5–3) | Oregon State (7–3) | Oregon State (7–3) | SMU (8–3) | 14. |
| 15. | Minnesota | Indiana (0–0) | Miami (FL) (1–0) | Tennessee (1–0–1) | Syracuse (2–1) | Texas Tech (3–0–1) | Florida (4–1) | Houston (3–1–1) | Oregon State (5–2) | Purdue (6–2) | Alabama (7–2) | Alabama (7–2) | Ohio (10–0) | Oregon State (7–3) | 15. |
| 16. | UCLA | Minnesota (0–0) т | Tennessee (0–0–1) | Georgia (1–0–1) | California (3–0) | Ole Miss (3–1) | Arkansas (4–1) | Michigan State (4–2) | Ohio (7–0) | Alabama (6–2) | Oregon State (6–3) | Missouri (7–3) | Missouri (7–3) | Auburn (7–4) | 16. |
| 17. | Arizona State | UCLA (0–0) т | Minnesota (0–1) | Texas A&M (1–1) | Georgia (2–0–1) | Texas (2–1–1) | Ole Miss (4–1) | Arkansas (5–1) | Michigan State (4–3) | Ohio (8–0) | Ohio (9–0) | Ohio (10–0) | Arizona State (8–2) | Alabama (8–3) | 17. |
| 18. | LSU | Georgia (0–0–1) | Oregon State (0–1) (1) | California (2–0) | Stanford (3–0) | Michigan (3–1) | LSU (4–1) | Florida State (4–1) | Auburn (5–2) | California (5–2–1) | California (6–2–1) | Auburn (6–3) | Houston (6–2–2) | Houston (6–2–2) | 18. |
| 19. | Syracuse | Miami (FL) (0–0) | Arizona State (1–0) | Michigan State (2–0) | Florida State (2–1) | Indiana (3–1) | Texas Tech (3–0–2) | Ohio (6–0) | Wyoming (6–2) | Indiana (6–2) | Auburn (6–3) | Arizona (8–1) | Florida State (8–2) | LSU (8–3) | 19. |
| 20. | Miami (FL) | LSU (0–0) | Wyoming (1–1) | Arkansas (2–0) | Oregon State (2–1) |
| Florida State (3–1) | Florida (4–1–1) | LSU (5–2) | Wyoming (6–2) | Wyoming (7–2) | Arizona State (7–2) | SMU (7–3) | Ohio (10–1) | 20. |
| Preseason Aug | Week 1 Sep 16 | Week 2 Sep 23 | Week 3 Sep 30 | Week 4 Oct 7 | Week 5 Oct 14 | Week 6 Oct 21 | Week 7 Oct 28 | Week 8 Nov 4 | Week 9 Nov 11 | Week 10 Nov 18 | Week 11 Nov 25 | Week 12 Dec 2 | Week 13 (Final) Jan | ||
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