This study focused on junior high school students’ perception of code-switching as a language pattern. It aimed to identify the level of students’ self-assessment of their English proficiency and their perception of code-switching when grouped according to sex, grade level, and academic performances in English subject and Filipino subjects. It employed the descriptive-quantitative method that used the adopted survey questionnaire proposed by Poplack (1995) which was modified by Alam (2016). The study respondents were 40 bilingual junior high school students of International School for Better Beginnings at Lucena City:- 20 of whom are males and 20 are females. Weighted mean and T-test were employed in analyzing and interpreting the data gathered. Analysis revealed that the students had a high English proficiency level as indicated by the overall mean of 4.06. This means that they could take part in conversations on a variety of topics. It was also revealed that there is a significant difference between the students’ perception of code-switching practices when they were grouped according to sex, grade level, and academic performances in English and Filipino subjects as registered by the computed values of 144.278, 466.606, 192.601, and 197.886, respectively. Moreover, the computed value of (p= 0.00) was lower than 0.05 level of significance, thus, the null hypothesis stating that there is no significant relationship between the students’ perceptions of code-switching practices when grouped according to sex, grade level, and academic performance in English and Filipino subject was rejected.