Eleventh grade (also known as 11th Grade, Grade 11, or Junior year) is the eleventh year of formal or compulsory education. It is typically the 3rd year of high school. Students in eleventh grade are usually 16-17 years of age.

In Australia, Year 11 is the twelfth year of education and fifth year of high school education. Although there are slight variations between the states, most students in Year 11 are aged around fifteen, sixteen, or seventeen. In Queensland, Year 11 students are the youngest in the country, as they usually enter at age fifteen.

In New South Wales, Year 11 is the shortest year as it only lasts three whole terms. Students commence Year 12 in Term 4 instead of completing a fourth term of Year 11.

Year 11 is followed by Year 12, the final year of high school.

In Bangladesh, students get admitted in the 11th grade after passing the Secondary School Certificate (SSC) examinations. Educational institutions offering the 11th–12th grade education are known as colleges. To study in the 11th grade, students must choose one of the three streams. (i.e., science, humanities, business studies.)

In Belgium, the 11th grade is called "5e secondaire" in the French speaking part of the country, "5de middelbaar" in the Dutch speaking part and "5te sekundäre" in the German speaking part of Belgium.

In Brazil, the eleventh grade is the "segundo ano do ensino médio", meaning "second grade of high school". Students tend to be 16 years old.

In Bulgaria, the 11th grade is the penultimate year of the high-school (gymnasium) stage. Students tend to be 17–18 years old.