This study aimed to evaluate the impact of an emergency online learning course on students' satisfaction, self-efficacy and achievement. This study used a convergent mixed methods approach with an action research design to explore students' experiences and outcomes in an emergency online science course. This study involved 25 voluntary participants from a private college in Manila, Philippines, who were enrolled in the Science, Technology and Society online course during the 2019-2020 academic year. Data were collected using a variety of instruments, including questionnaires, reflective journals and semi-structured interviews. The results showed that the developed emergency online learning course positively impacted students' satisfaction, efficacy and achievement. Students were satisfied with their interactions with classmates and teachers and the course content. They also expressed confidence in their ability to perform online tasks independently and master the subject through pre-recorded videos. This study suggests that effective student-teacher interaction, peer relationships, relevant and relatable course content, well-designed lesson materials, clear assessment tasks, differentiated tasks to meet individual learning preferences and teacher creativity are essential factors for student satisfaction, efficacy and achievement in emergency online learning courses.