This study that adopts descriptive and inferential research methods investigated the status of elementary grade pupils' English proficiency, particularly the Grades 1, 2 and 3 pupils who are simultaneously taking up subjects in the Mother Tongue and English that are integrated in their curricula. The research population was sourced from a single research locale, i.e. Don Amadeo Perez Sr. Memorial Central School-Main, during the SY 2017-2018. The study employed content-validated data-gathering instruments. The pupils across the three curriculum grades have varied sociodemographic and language-learning characteristics. Sex-distribution in the three grade levels have different ratios. Regardless of curriculum grade designation, the pupils' mother tongues range from "Ilokano", "Tagalog", and "English". The family income of all the pupils regardless of curriculum grade are differentiated and range from "Very High", "High", "Above Average", "Average", "Low", and "Very Low". Across the three grade levels, the pupils' academic performance in English registered into different levels from "Outstanding" (maximum) to "Fairly Satisfactory" (minimum). Most of the pupils in each group registered densely in the lower strata of performance levels. Their academic performance in Mother Tongue registered in the levels of "Outstanding" (maximum) to "Fairly Satisfactory" (minimum). Grades 1, 2, and 3 pupils' English proficiency levels range from "High" (maximum) to "Low" (minimum). Relationship between the profile variables and English proficiency is dependent on the grade level of students. None of the profile variables are significantly related to EPL in the accounts of the Grade 2 pupils. Grade 1 pupils account for a significance in relationship between "academic performance in mother tongue" and EPL. Grade 3 pupils account for a significance in relationship between EPL and "sex", "academic performance in Mother Tongue" and "academic performance in English". Teachers vary as to their level of agreement or disagreement on the positive or negative implications of the MTB-MLE policy in the English proficiency of pupils. Based on the aforementioned gist of research findings, several recommendations were offered to improve instructional efficiency and strategies that can alleviate pupils' difficulties and limitations in their English proficiency as well as their academic performance in English subjects. This shall be done adjacently as they are also expected to equally develop linguistic skills in their Mother Tongue. These involve the initiative and cooperation among the concerned English language and Mother Tongue teachers, the School management, and the pupils. Recommendations were also addressed for future researchers to continue their scholarly investigation on the effects or implications of the adjacent learning of Mother Tongue and English prescribed by the MTBMLE policy of the Department of Education (DepEd).