Israel's Education Ministry invited proposals for the development of a new multilingual policy for the country's education system. We submitted a proposal for an 'engaged language policy' approach, which helps schools to conceptualize and develop a policy that best fits them ideologically and demographically. This study aimed to map teachers' and students' attitudes toward various principles and practices of multilingual education in order to gather baseline data for the policy. It consisted of a mixed method design that included 2,157 Jewish and Arab teachers and students. Results showed a positive stance toward a multilingual policy and general readiness to implement it. There was overall support for expanding the range of languages offered and for strengthening immigrants' languages, beside positive attitudes toward Arabic and Hebrew instruction for Jews and Arabs, respectively, together with various reservations, especially about translanguaging and accommodations for immigrants. Several differences emerged between Jews and Arabs, reflecting essential gaps between them regarding language and identity in Israel. The findings provide a basis for developing the new policy on more stable ground, adjusting its central principles to different contexts and implementing it gradually, enabling each school to design its own language policy based on its own ideology and demography.