This study investigates English-Tagalog code-switching in English language classes in Metro Manila, the Philippines. A corpus containing a total of 14 English language classes was analyzed to determine how frequent teachers and students code-switch in those classes and bring to light the forms and functions of the code-switches of both the teachers and students. The analysis of the data reveals that most English language teachers in the sample code-switch; students likewise code-switch in their English language classes. Instances of English-Tagalog code-switching in the corpus are mostly smooth switches. Following a preliminary analysis using Mattsson and Burenhult-Mattsson’s typology (1999) on the functions of teacher code-switches and Eldridge’s (1996) on student code-switches, a new typology is proposed to better capture the psycho-sociolinguistic reality of English-Tagalog code-switching in English language classes in Metro Manila, the Philippines. The new typology proposed is a unified one; it does not distinguish code-switches made by teachers and code-switches made by students. What is differentiated in the new typology proposed is whether a code-switch is made intentionally or involuntarily. Based on the analysis, it is argued that code-switching should not be seen as detrimental to the learning process, even in the learning of languages. Code-switching could be a useful technique in the language classroom for both teachers and students in learning a target language, even if a speaker is switching to a language which is not the target language.