We present the first description of a breeding record of the Harpy Eagle (Harpia harpyja) in Belize, and describe the subsequent fledging of the juvenile. We discovered the nest on 27 November 2010 with a single 4–5 week-old chick, and began focal observations. The juvenile spent 56.3% of 71 observation days feeding, and the parents delivered food to the nest at a rate of one item every 2.04–3.33 days from late January to April. The most frequent food items were the common opossum (Didelphis marsupialis), white-nosed coatimundi (Nasua narica), and Yucatan black howler monkey (Alouatta pigra). We placed a satellite GPS-PPT transmitter on the juvenile Harpy Eagle on 14 April 2011 to track its movement patterns after fledging. Soon after, the parents stopped returning to the nest, the juvenile fledged, and for 28 days we delivered food to the young eagle in place of its parents. The abandonment of the juvenile by the parents may have been caused by low food abundance caused by drought conditions and/or placement of the transmitter may have had a role. The male subsequently returned to feed the juvenile. We believe these eagles represent one of the northernmost known extant breeding pairs of Harpy Eagles in the Americas.