Self-determination theory (SDT) is a significant theoretical framework for investigating and comprehending student learning and motivation, which are crucial aspects of physical education. The purpose of this study is to identify the reliability and validity of the Malay language version of SIMS-14 items, as well as to determine the effect of four-week intervention teaching utilizing the flipped classroom method affects primary school students' situational motivation. A total of 421 students participated in this study. Reliability analysis based on the Rasch model found that the individual reliability value was 0.91 and the items reliability was 0.85. CFA analysis reported X[superscript 2]/df = 2.037, CFI = 0.969, GFI = 0.907 and RMSEA = 0.074 with internal validity for each variable based on Cronbach Alpha's ([alpha]) values ranging from 0.87 to 0.92. As for the value of Construct Validity (CR), the value of 0.88 to 0.95 is obtained by fulfilling the condition [greater than or equal to] 0.60 and the value of Average Variance Extracted (AVE) is between 0.70 to 0.86. Therefore, the data collected using SIMS-14 items were analyzed with One-Way ANCOVA and the results affirmed that students from the experimental group exhibited an enhancement in situational motivation based on flipped classroom method better than the control group. Besides, the results of the study revealed that the SIMS-14 items consist of four factors that are consistent and prove the quality of psychometry. In addition, the SIMS-14 items instrument attempts to represent constructs of intrinsic motivation, identified regulation, external regulation, and amotivation that can be widely used for assessment in the context of PE.