Methods and apparatus to identify exposure to three dimensional media presentations are disclosed. An example method includes detecting a first brightness level with a first sensor and a second brightness level with a second sensor at a first time. A third brightness level is detected with the first sensor and a fourth brightness level is detected with the second sensor at a second time later than the first time. A 3D media counter is incremented when either: the first brightness is greater than the second brightness and the third brightness is less than the fourth brightness, or the first brightness is less than the second brightness and the third brightness is greater than the fourth brightness. The media is identified as 3D media when the 3D media counter exceeds a threshold.