The Third International Mathematics and Science Study, known as TIMSS 1995, was the largest and most ambitious international study of student achievement conducted up to that time. In 1994–95, it was conducted at five grade levels in more than 40 countries (the third, fourth, seventh, and eighth grades, and the final year of secondary school).

Students were tested in mathematics and science and extensive information about the teaching and learning of mathematics and science was collected from students, teachers, and school principals. Altogether, TIMSS tested and gathered contextual data for more than half a million students and administered questionnaires to thousands of teachers and school principals.

Also, TIMSS investigated the mathematics and science curricula of the participating countries through an analysis of curriculum guides, textbooks, and other curricular materials. The TIMSS results were released in 1996 and 1997 in a series of reports, providing valuable information to policy makers and practitioners in the participating countries about mathematics and science instruction and the achievement of their students. Technical reports and the complete international database also have been published.

TIMSS 1995 was a project of the TIMSS & PIRLS International Study Center at Boston College.