The purpose of this study was to develop predictive models of student test-taking engagement in computerized formative assessments. Using different machine learning algorithms, the models utilize student data with item responses and response time to detect aberrant test behaviors such as rapid guessing. The dataset consisted of 7,602 students (grades 1 to 4) who responded to 90 multiple-choice questions in a computerized reading assessment two times (i.e., fall and spring) during the 2017-2018 school year. We completed data analysis in four phases: 1. A response time method was used to label student engagement in both semesters; 2. The training data from the fall semester was used for training the machine learning models; 3. The testing data from the fall semester was used for evaluating the models and 4. The spring semester was used for model evaluation. Among the different algorithms, naive Bayes and support vector machine which were built on response time data from the fall semester, out performed other algorithms in predicting student engagement in the spring semester in terms of accuracy, sensitivity, specificity, area under the curve, kappa, and absolute residual values. The results are promising for early prediction of student test-taking engagement to intervene with the test administration and ensure that the validity of test scores and inferences made based on them.