Reclaimer is a title, possibly bestowed by the Forerunners, in the computer game Halo: Combat Evolved.

The task of a Reclaimer is to recover the "Index" and return it to the Halo control center. Doing this would activate Halo's ability to destroy all organic life within twenty-five thousand light years, and would also activate other Halos, causing the entire galaxy to be purged of organic life. This would be done to prevent the spread of The Flood, which can only be accomplished by destroying all organic life it can survive on. Essentially destroying the Flood through starvation.

343 Guilty Spark (supposedly) incorrectly assumed, for unknown reasons, that the Earth soldier Master Chief was a Reclaimer.

According to the Halo novels, there is a possibility that Reclaimers are chosen by someone who is still alive and active somewhere.

The above is one possible interpretation. It is not stated explicitly in either gameplay or literature that Reclaimer is even a title. Another interpretation is that a Reclaimer is the Forerunner terminology for a human. Neither The Master Chief nor Commander Keyes are ever referred to as the Reclaimer. The Monitor always uses the terms Reclaimer, a Reclaimer, or this Reclaimer. From this it is possible to assume that the Forerunners had knowledge of humans and delegated to them the task of Reclaiming Indexes and activating the rings, among many, many other speculative duties. It is also speculated that the Forerunners were human, or at least, very closely related, perhaps being direct ancestors or future form of humanity. There is evidence to prove this, such as 343 Guilty Spark's statements in the first game, and the fact that the Covenant have not asked humanity to join them. This, as is much of the Halo universe, is all highly speculative.