The research focuses on the development and validation of an integrated assessment instrument to assess students' analytical thinking skills and chemical literacy in chemical equilibrium. The research consists of 5 phases ie analysis, design, development, implementation, and evaluation. The research participants were 174 students of grade 12th senior high schools in Yogyakarta, Indonesia. The participants were selected using stratified random sampling. The Integrated assessment instrument to assess students' analytical thinking skills and chemical literacy consists of 20 open-ended multiple-choice questions developed from 12 integrated indicators. Expert validation result shows that 20 questions are declared valid with Aiken's V value greater than 0.86. The result was collated and coded for analysis with Rasch model approach. 3 items (15%) were included in the very difficult category, 3 items (15%) were included in the difficult category, 8 items (40%) were included in the moderate category, 5 items (25%) were included in the easy category, and 1 question (5%) was included in the very easy category. It turns out that this instrument is capable to measure students' analytical thinking skill and chemical literacy.