This study aims to identify functions (Note 1) of teachers’ first language (L1) use in English as a foreign language (EFL) classes in public schools in Jordan based on students’ observations. The questionnaire items were selected based on the most common uses of L1 in second language (L2) classrooms as identified in the literature. The questionnaire was designed to elicit students’ observations to identify functions of EFL teachers’ L1 in English classes. The participants were 104 EFL students in Grades 10 and 11 in four Jordanian public schools. Participants’ responses to the questionnaire were analysed quantitatively using SPSS, a statistical software package. The study found that the students observed that their teachers shared their L1 with them in English classes to: 1) Explain complex grammar points, 2) Define some new vocabulary items, 3) Explain difficult concepts or ideas, 4) Give instructions, 5) Praise the students, 6) Translate the reading texts, and 7) Explain the similarities and differences between Arabic and English in terms of grammar, structure or pronunciation. However, the students did not observe that their teachers used the L1 in order to maintain discipline in the class as previous studies have found. The findings suggest that teachers’ L1 use in the L2 classroom may indicate the usefulness of this practice and call to license EFL teachers to use their L1 in English classes in public school in Jordan and other similar EFL contexts.