The southern green stink bug, Nezara viridula L., may disperse from alternate host plants, especially corn, Zea mays L., and peanuts, Arachis hypogaea L., into cotton, Gossypium hirsutum L. Trap crops may be useful to intercept dispersing stink bugs. Therefore, the ability of sorghum, Sorghum bicolor L. Moench, to trap N. viridula adults in cotton was studied for 3 yr. The 2002 experiment was designed to compare the ability of small plots of sorghum and cotton to trap N. viridula along the interface, or common boundary, of a corn and cotton field. In the 2003 experiment, cotton fields with sorghum and cotton plots planted along the interface of a corn–cotton farmscape were compared with cotton fields without these interface plots. In both experiments, N. viridula adults strongly preferred sorghum to cotton, and marking studies revealed that most N. viridula adults that dispersed into sorghum remained in sorghum instead of moving into cotton. Overall, percent parasitism of N. viridula adults by T. pennipes was higher in sorghum trap crop plots than in interface cotton control plots. In 2003, density of N. viridula adults was lower in cotton fields adjoining sorghum trap crop plots than in control cotton fields. Furthermore, economic threshold for N. viridula was not reached along the interface of the corn–cotton farmscape in any cotton field with sorghum plots. In contrast, economic threshold was reached in 61.5% of the control cotton fields. In the third season, a full-scale field experiment was conducted to determine the effectiveness of sorghum, planted in a strip along the length of the interface of a peanut–cotton farmscape, as a trap crop in cotton. Before the test, each cotton field was partitioned into eight side-edge and three interior block locations. Each field had four sides with side A occurring along the interface of the field. Edge 1 was 0–3.66 m from the outside edge of the field, and edge 2 was 3.66–7.31 m from the outside edge of the field. In control cotton fields, density of N. viridula adults was much higher in the interface side in edge one than in any other side-edge location, strongly indicating that N. viridula adults dispersed from peanuts into these cotton fields. Control cotton fields had higher numbers of N. viridula adults in the interface side in edge one compared with cotton fields with sorghum trap crops. Overall, in 2004, control cotton fields were treated with insecticides for control of N. viridula 1.4 times, whereas cotton fields with sorghum trap crops were treated for control of this stink bug only 0.2 times. These results show that sorghum can serve as a trap crop for N. viridula adults in cotton fields.