This study examined and compared how the trajectories of two types of implicit theories (IT; general intelligence and emotional intelligence EI) evolve over the 3-year period of the Portuguese secondary school period. The effects of students' gender, academic achievement, and EI on the developmental path of IT were also explored. Two hundred twenty-two students participated in a 3-wave study from 10th to 12th grade, were aged 14 to 18 years old (M[subscript age]= 15.4; SD = 0.63) in the first round of data collection, and were mostly female (58.6%). The findings indicate the stability of students' implicit beliefs of intelligence over secondary school and, in turn, the continuous evolution of students' incremental IT of EI. Students' gender and previous levels of trait EI influenced the IT's change patterns. The findings are discussed based on the relevance of the educational context to foster incremental beliefs about school-related attributes for all students.