Objective To develop a measure of transition readiness and assess factors associated with perceived readiness for transition of healthcare responsibility and transfer among adolescent kidney transplant recipients. Methods The Readiness for Transition Questionnaire (RTQ-teen; RTQ-parent) was created to assess overall transition readiness, adolescent healthcare behavior, and familial involvement in healthcare. Participants were 48 adolescent kidney transplant recipients ages 15–21 years. Thirty-two (66.7%) of the adolescents’ caregivers also participated. Adolescents completed the RTQ-teen, as well as self-reported measures of adherence and barriers to adherence. Parents completed the RTQ-parent. Results The RTQ showed good internal consistency, inter rater reliability, and demonstrated construct validity. Increased adolescent responsibility and decreased parental involvement predicted higher transition readiness. Additionally, greater adolescent adherence factors predicted greater transition readiness. Conclusions The preliminary psychometrics of the RTQ appear to be supported. Additional research should evaluate healthcare transition programming to identify clinical components related to improved transition readiness, adolescent responsibility, and medical outcomes.