This work is a textual study of the Gospel of John as it is preserved in the catena compiled by Nicetas of Heraclea. In part 1, a stemma is drawn up based on an examination of full transcriptions of all known witnesses: Gregory-Aland 249 317 333 423 430 743 869. Though some scholars have stated that G-A 841 886 1178 2188 contain the catena as well, closer examination shows they contain other works. The manuscripts of Nicetas are related as follows: 1) 249 333 423 are descendants of a common ancestor, β; 2) 333 was the exemplar for 423; 3) 317 869 are descended from a common ancestor, γ; 4) 430 is an independent witness with an idiosyncratic text; 5) 743 has a high degree of majority text contamination and an unclear relationship with the other witnesses. The second part of the study consists of a reconstruction of Nicetas’s text of John with a full apparatus.