The problem of this study was to investigate and develop a reliable and valid instrumentation for measuring both the trait and state curiosity of junior high school students. In an effort to evaluate as many curiosity types as possible, the Trait-State Curiosity Inventory for Junior High School Students was developed to measure four types of curiosity--manipulatory curiosity, perceptual curiosity, conceptual curiosity, and curiosity about the complex or ambiguous;The sample for this study consisted of 509 seventh and eighth grade students who were enrolled at Neveln Junior High School, Ankeny, Iowa, in May of 1985. The Trait-State Curiosity Inventory for Junior High School Students was administered once to each student during the third class period on one of three possible testing days. There were 12 seventh grade and 12 eighth grade classes involved in this study. All classes were intact, and no treatments nor control groups were used in this study;The Trait-State Curiosity Inventory for Junior High School Students was found to have high internal consistency and supportive content and concurrent validity. Positive correlations were found between the following: (1) teacher evaluations of student curiosity and student responses on the trait-state curiosity measure and its subtests; (2) GPA and student responses on the total trait-state curiosity measure; (3) GPA and student responses on the subtests of the trait curiosity measure; (4) GPA and student responses on the perceptual curiosity, conceptual curiosity, and curiosity about the complex or ambiguous subtests of the state curiosity measure; and (5) the sex of the students who participated in this study and their responses on the perceptual curiosity subtests of the trait-state curiosity measure;A factor analysis of the intercorrelations between subtests of the trait-state curiosity measure is needed to identify the different dimensions of curiosity and their nature; and, also, the distinction between curiosity as a trait and curiosity as a state needs extensive supporting research.