Interpersonal Conflict, Agreeableness, and Personality Development Lauri A. Jensen-Campbell Katie A. Gleason University of Texas at Arlington Ryan Adams Florida Atlantic University Kenya T. Malcolm University of Texas at Arlington ABSTRACT This multimethod research linked the Big-Five person- ality dimensions to interpersonal conflict in childhood. Agreeableness was the personality dimension of focus because this dimension has been associated with maintaining positive interpersonal relations in adoles- cents and adults. In two studies, elementary school children were assessed on the Big-Five domains of personality. Study 1 (n 5 276) showed that We thank Shaun D. Campbell for his help with computer programming and Doran French, William G. Graziano, and Gary Lautenschlager, for advice on aspects of this research. We thank Denise Benkert, Tina Burns, Janine Furdella, Jeff Garbe, Adair Garner, Lee Haiber, Susan Levitt, Justin Rigsbee, Jasmin Rios, and Martina Soltez who provided help in completing the data collection. We also thank Michael Bilton, Dan Wilcox, Jessica Faiella, Kim Mathieson, Julie Norman, Heather O’Hara-Bassuk, Neha Patel, Yanisha Willis, Jasmin Rios, Jose Velarde, and Amber Zehnder for all of their pain-staking work coding the conflict observations. We gratefully acknowledge the cooperation of the faculty and students of A.D. Henderson University School, St. Bernadette’s School, Davie Elementary, Griffin Elementary, Nova Southeastern Elementary, and St. Ambrose School. A National Institute of Mental Health B/Start Grant to L.A. Jensen-Campbell supported parts of this research. Communications about this research may be directed to L.A. Jensen-Campbell, Department of Psychology, University of Texas at Arlington, Box 19528, Arlington, Texas 76019- 0528. Tel.: 817-272-5191, e-mail: lcampbell@uta.edu. Journal of Personality 71:6, December 2003. Blackwell Publishing 2003