This research has aimed to: 1) determine the feasibility of guided inquirybased learning instrument to develop students' scientific literacy on reaction rate in 11th grade senior high school students and 2) determine the effectiveness of guided inquiry-based learning instrument to develop students'scientific literacy on reaction rate in 11th grade senior high school students. The type of research was research and development (R&D). The development model used is the ADDIE model which has stages of analysis, design, development, implementation, and evaluation. The instrument developed was implemented on 65 students from SMAN 1 Mojolaban and SMAN 1 Polokarto, Sukoharjo Regency. The product developed is a learning instrument, consisting of lesson plans, textbooks, and science literacy test about rate of reaction for 11th grade senior high school. The feasibility of learning products is calculated based on the results of the validation analysis using Aiken's validation while the effectiveness of learning instruments based on the results of the Independent Samples T-Test on the N-Gain score of scientific literacy. The results of the validation analysis on the learning instrument showed that validity coefficient more than 0.73 meant that it was eligible to use. The textbook developed received a very good response from students and teachers and it is suitable for use. In the effectiveness test, the significance value was less than 0.05 and t-count> t-table, so it could be concluded that guided inquiry-based learning instruments were effective in developing students' scientific literacy on the reaction rate. The increase in students' scientific literacy skills was categorized as high based on the N-Gain score of more than 0.7.
