In the rapidly growing Business Process Outsourcing (BPO) industry in the Philippines, effective communication plays a vital role in ensuring quality customer service and maintaining customer satisfaction. Call center agents are expected not only to possess grammatical and linguistic competence but also to demonstrate sociolinguistic competence, which involves the appropriate use of language according to social and cultural contexts. Despite the importance of communication in the BPO sector, challenges such as language barriers, cultural misunderstandings, code-switching, and inappropriate communication styles continue to affect customer interactions and service outcomes. This study aimed to determine the level of sociolinguistic competence of selected call center agents in the Philippines and examine its impact on customer satisfaction. Specifically, the study focused on language appropriateness, cultural sensitivity, conversational strategies, and pragmatic competence in customer interactions. Furthermore, it sought to identify whether a significant relationship exists between sociolinguistic competence and customer satisfaction. The study employed a quantitative descriptive research design. Data were gathered through interview and structured survey questionnaires administered to selected call center agents from BPO companies in the Philippines. The study found that selected call center agents possess a high level of sociolinguistic competence in terms of appropriateness of language use, code-switching and style shifting, cultural sensitivity, and pragmatic competence. They are capable of adjusting their language, tone, vocabulary, and communication style based on the customer‟s background, emotional state, and level of understanding while maintaining professionalism and respect. The findings also showed positive customer communication outcomes, as customers frequently expressed gratitude, became calmer after clear explanations, used positive language, followed instructions, acknowledged issue resolution, and gave high satisfaction ratings. This indicates that effective communication behavior among call center agents significantly contributes to customer satisfaction, successful service interactions, and overall service quality. The study concludes that selected call center agents demonstrate a high level of sociolinguistic competence in language use, code-switching, cultural sensitivity, and pragmatic competence, which enables them to communicate effectively and professionally with diverse customers. Their ability to adapt language, show empathy, and handle customer concerns appropriately contributes to positive customer communication outcomes such as gratitude, cooperation, issue resolution, and high satisfaction ratings. While company scripts provide structure and consistency, flexibility, personalization, and strong communication skills remain essential in building customer trust and satisfaction. Therefore, a training module titled "Enhancing Sociolinguistic Competence for Effective Customer Communication in the Call Center Industry" can be utilized by call center companies and training institutions to strengthen agents' communication skills.