Background: Assessment is crucial for the quality of teaching and learning in physical education (PE). Currently little is known about the students' level of achievement in PE and about the parameters used for calculating the PE grades. Although there is evidence that boys are more active outside school than girls and participate more in organized sports, few studies have examined possible differences between genders in PE achievement. Furthermore, despite the current interest in the relationship between motor competencies and cognitive functioning, limited research has examined if PE grades are associated with academic achievement. Purpose: Considering the lack of information on the current level of students' success in PE, the main aim of this study is to examine the PE grades of Portuguese students in secondary school. Specifically, this study analyzes the level of students' achievement in PE, the relation of PE grades with other school subjects' grades, compares the PE grades between boys and girls, and presents the PE summative assessment parameters used in schools. Method: Participants were 1936 students (57% girls) from the 10th, 11th and 12th grades (16.8 ± 1.3 years old) attending eleven Portuguese secondary schools. Information was gathered on their grades in PE and in the other school subjects at the end of the school year. Information on the specific assessment parameters used in each school was also collected. Results: The average grades in PE were 14.9 ± 2.3 points (20-point scale). Only ~1% of students with a final PE grade had a negative performance (<10 points). PE grades were relatively higher than in most of the other school-subjects and for most students (68.7%) the PE classification raised their overall average grade. The level of correlation between grades in PE and in other school subjects was statistically significant (r's = 0.13 to 0.29, p < 0.05) although lower than that between grades in the other school subjects (r's = 0.44 to 0.84, p < 0.01). There were significant differences between girls' and boys' grades in PE (14.3 ± 2.3 and 15.9 ± 2.1 points, respectively). The school assessment parameters prioritize physical performance over participation and attitude. Conclusion: The Portuguese students' level of achievement in PE seems to be very satisfactory. However, as boys have higher grades than girls it is urgent to find appropriate strategies to tackle this problem. The associations found between PE grades and academic achievement could have relevant repercussions considering the current debate about the status of PE and about the relationship between motor and cognitive competencies. It is also relevant that the schools' summative assessment parameters are based mainly on skill mastery and not on effort and participation. This study provided a brief glance into some aspects of the assessment of PE in Portugal and is it is desirable that future investigations examine the teacher's assessment practices.