Fear of Missing Out (FoMO) and Nomophobia are two things that often happen to young adults in this globalization era. Both of these also have a correlation with attachment. This study aims to examine 158 emerging adults in Greater Jakarta regarding the relationship between FoMO and Nomophobia mediated by Attachment. The research was conducted using quantitative methods and mediational tests using the Fear of Missing Out Scale (FoMOs), Nomophobia Questionnaire (NMP-Q), and The Experiences in Close Relationships-Revised General Short Form (ECR-R-GSF) measuring instruments/Fear of Missing Out (FoMO) dan Nomophobia merupakan dua hal yang sering terjadi bagi para dewasa muda pada era globalisasi ini. Kedua hal tersebut juga memiliki korelasi dengan attachment. Studi ini bertujuan untuk meneliti 158 emerging adulthood di Jabodetabek mengenai hubungan antara FoMO terhadap Nomophobia dimediasi oleh Attachment. Penelitian dilakukan dengan metode kuantitatif dan uji mediasional dengan alat ukur Fear of Missing Out Scale (FoMOs), Nomophobia Questionnaire (NMP-Q), dan The Experiences in Close Relationships-Revised General Short Form (ECR-R-GSF).