This study investigated the pattern of growth in syntactic fluency of college-preparatory students in grades 7-12. Its primary purpose was to examine the syntactic structures employed in samples of narrative writing by the 12 different groups (totaling 216 students) that comprised the study sample. A secondary purpose was to determine which of four indices of maturity in writing (mean subordinate clause length, subordination ratio, mean T-unit length, and mean level of embedding or attaching) was the best measure of growth. Data were obtained from school records and from an investigator-constructed instrument composed of 76 kernel-like T-units which students were to combine. Some of the findings were that (1) while the mean depth index increased progressively until the 11th grade, mean T-unit length, mean subordinate clause length, and subordination ratio increased only until the 10th grade, followed by slight regressions in the subsequent grade levels, (2) significant differences were found among the six grade levels for each of the four indices, (3) contingency coefficients revealed that mean T-unit length was the best measure of maturity in writing, and (4) syntactic structures which appeared in the writing at the higher grade levels also appeared in the writing of younger students. (Author/DD)