In this paper, it is aimed to evaluate different aspects of students' response time to items in the mathematics test and their test effort as an indicator of test motivation with the help of some variables at the item and student levels. The data consists of 4th-grade Singapore and Turkish students participating in the TIMSS 2019. Response time was examined in terms of item difficulties, content and cognitive domains of the items in the mathematics test self-efficacy for computer use, home resources for learning, confident in mathematics, like learning mathematics, and gender variables at the student level. In the study, it was determined that all variables considered at the item level affected the response time of the students in both countries. It was concluded that the amount of variance explained by the student-level variables in the response time varied for each the country. Another finding of the study showed that the cognitive level of the items positively related to the mean response time. Both Turkish and Singaporean students took longer to respond to data domain items compared to number and measurement and geometry domain items. Additionally, based on the criterion that the response time effort index was less than 0.8, rapid-guessing behavior, and therefore low motivation, was observed below 1% for both samples. Besides, we observed that Turkish and Singaporean students were likely to have rapid guessing behavior when an item in the reasoning domain became increasingly difficult. A similar result was identified in the data content domain, especially for Turkish graders.