The interpretive ease and intuitive appeal of the Holland RIASEC typology have made it nearly ubiquitous in vocational guidance settings. Its incorporation into the Occupational Information Network (O*NET) has moved it another step closer to reification. This research investigated the rates of agreement between Holland code classifications from three major sources. The Holland code classifications from the O*NET were compared with those from the Strong Interest Inventory and the Dictionary of Holland Occupational Types using six different methods. The mean pairwise rate of agreement for the first Holland code letter was 70.6%, with a three-way rate of agreement of 60.21%. The mean pairwise rate of agreement for the first and second Holland code letters was 32.33%, with a three-way rate of agreement of 15.71%. The mean pairwise rate of agreement for the first, second, and third Holland code letters was 12.56%, with a three-way rate of agreement of 2.62%. The implications of these findings for research and counseling practice are discussed.