The aims of this study were to analyze the psychometric properties of the Spanish version of the Three-Factor Eating Questionnaire-R18 (TFEQ-SP), as well as determine its validity by evaluating the relationship of the TFEQ-SP with different parameters related to body mass index, weight perception, perception of physical fitness, self-esteem, and food intake, as well as with weight control-related variables. A total of 281 participants (aged 18.38 ± 6.31) were studied. The factor analysis yielded three factors: cognitive restraint (CR), uncontrolled eating (UE), and emotional eating (EE). The internal consistency of the TFEQ-SP was determined by means of Cronbach’s α coefficient, with values ranging between 0.75 and 0.87. Higher scores on CR were found in women (p < 0.5), overweight/obese participants (p < 0.001), participants with lower self-esteem (p < 0.05), participants who overestimated their weight (p < 0.001), participants who weighed themselves frequently (p < 0.001) and those who were about to go on a diet (p < 0.001). Higher EE scores were found in participants with lower self-esteem scores (p < 0.05), among participants with a poorer perception of their physical fitness (p < 0.01) and when participants were about to diet (p < 0.05). Higher scores on UE were observed in case of poorer perception of physical fitness (p < 0.05). The validation study of the TFEQ-SP meets the requirements for measuring the three different facets of eating behavior: CR, UE, and EE.