One important theme of "Shooting an Elephant" is the conflict between conscience and imperialism. The narrator does not want to shoot the elephant, but the crowd is clamoring for him to do so, and if he does not, he will be ridiculed and reviled by them, thus weakening his power:
And suddenly I realized that I should have to shoot the elephant after all. The people expected it of me and I had got to do it; I could feel their two thousand wills pressing me forward, irresistibly. And it was at this moment...that I first grasped the hollowness, the futility of the white man's dominion in the East. Here was I, the white man with his gun, standing in front of the unarmed native crowd — seemingly the leading actor of the piece; but in reality I was only an absurd puppet pushed to and fro by the will of those yellow faces behind.
This relates to a second major theme in the piece, which is the relationship between the imperial power, represented by the narrator, and the Burmese people. It is highly complex and contradictory. They hate him because he represents a violent colonizing force. But at the same time, he must use violence to satisfy them, by living up to their view of him as a villain. Either way, he cannot escape their contempt, which he describes throughout in other contexts.
Finally, there is the theme of order (and, perhaps, disorder.) The narrator, as a colonial policeman, is tasked with maintaining order. Ironically, order has already been achieved by the time he is called upon to shoot the elephant. It has, after its brief rampage through the bazaar, been pacified and tied up. However, the mob threatens a different kind of disorder, and to placate them, he must kill the elephant, giving in to disorder in order to maintain order, in a sense.