The study is aimed at exploring teacher's strategies in designing bilingual test items in science and mathematics. Through employing a qualitative approach and using an interview to collect the data, the study involves an elementary teacher in a private school that implements a bilingual program in the classroom. The study reveals several findings: 1) the teacher uses a simplified language for the items; 2) given students' barrier in terms of understanding specific terms, the teacher aids the students by using L1 to ensure students' understanding; 3) because of students' limited English proficiency, the teacher cautiously chooses the familiar words in the items to be translated into English; 4) the teacher seeks help to ensure the test items are understandable. This is an open access article distributed under the CC BY-NC 4.0 license -http://creativecommons.org/licenses/by-nc/4.0/. 63The study is to seek teacher's strategies on designing bilingual (Indonesian-English) test items in an elementary school that enacts the bilingual program in which mathematics and science are taught in English. The textbooks of math and science used by the teacher in the classroom are bilingual; English and Indonesian. Meanwhile, the content areas are