Image is one of the quality characteristics most associated to the group exercise fitness instructor (GEFI). This study intends to: characterize the importance attributed to the image of the GEFI, by instructors and participants; compare the importance attributed to the image of the GEFI, between instructors and participants; associate the importance attributed to the image of the GEFI, by instructors and participants, with age, experience and education. 102 instructors (29.66 ± 5.95 years) and 150 practitioners (37.72 ± 15.14) participated. Data were collected using the questionnaire of Szumilewicz et al. (2008), translated, adapted and validated for Portugal. The characterization was performed using descriptive statistics (M ± SD). For comparison, the t test for independent samples was used. For the association between the importance attributed to the age and experience, the Pearson correlation test was used. Between attributed importance and the level of education, the Spearman correlation test was used. In the characterization, it was possible to verify which items were given greater or lesser importance, and which were associated with the GEFI image. By comparison, it was possible to verify significant differences in eight of the 15 items (e.g., sense of humor). Through the association of variables, it was possible to perceive the significant relationships between the importance attributed to the image of the GEFI according to the age, experience and education of the participants and the instructors themselves. It is concluded that image is a quality attribute that the fitness instructor must pay attention to when providing the service. Keywords: image; instructor; fitness; age; experience; education.