A computer-implemented method for deduplicating archived data may include (1) identifying a volume of data subject to deduplication, with the volume of data comprising at least one archived file that is represented on the volume of data with a placeholder file and is stored on an alternate volume of data, and (2) determining a disposition of the archived file for deduplication by (i) determining that the archived file is represented by the placeholder file, and, in response to determining that the archived file is represented by the placeholder file, (ii) identifying a deduplication fingerprint of the archived file instead of a deduplication fingerprint of the placeholder file. Various other methods, systems, and computer-readable media are also disclosed.