| Competition: | Campeonato Nacional Apertura Petrobras |
| Dates: | 27 January – 2 July 2012 |
| Season: | 2012 |
| Winners: | Universidad de Chile 15th title |
| Continentalcup1: | 2012 Copa Sudamericana |
| Continentalcup1 Qualifiers: | O'Higgins Deportes Iquique |
| League Topscorer: | Enzo Gutiérrez Sebastián Ubilla Emanuel Herrera (11 goals) |
| Biggest Away Win: | Audax Italiano 0-6 Universidad de Chile (10 March) |
| Highest Attendance: | 44,198 Universidad de Chile 2–1 O'Higgins (2 July) |
| Attendance: | 5,253 |
| Average Attendance: | 877,334 |
| Matches: | 167 |
| Total Goals: | 475 |
| Prevseason: | 2011–C |
| Nextseason: | 2012–C |
The 2012 Campeonato Nacional Apertura Petrobras was the Chilean football top tier’s 90th season. Universidad de Chile was the tournament's champion, after beating O'Higgins on penalties, in the finals.
In the quarterfinals, the 1 seed play the 8 seed, the 2 seed play the 7 seed, the 3 seed play the 6 seed, and the 4 seed play the 5 seed.
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In the semifinals, the highest seed play the lowest seed, and the second-highest seed play the second-lowest seed.
----Universidad de Chile won 4–2 on aggregate.
----2–2 on aggregate. O'Higgins won on away goals rule.
----3–3 on aggregate. Universidad de Chile won on penalties.
| Player | Club | Goals |
|---|---|---|
 Emanuel Herrera | Unión Española | 11 |
| Sebastián Ubilla | Santiago Wanderers | 11 |
| Enzo Gutiérrez | O'Higgins | 11 |