The invention provides an isolated or purified T cell receptor (TCR) having antigenic specificity for NY-ESO-1. Also provided are related polypeptides, proteins, nucleic acids, recombinant expression vectors, isolated host cells, populations of cells, antibodies, or antigen binding portions thereof, and pharmaceutical compositions. The invention further provides a method of detecting the presence of cancer in a mammal and a method of treating or preventing cancer in a mammal using the inventive TCRs or related materials.