Phelan-McDermid syndrome (PMS) is a neurodevelopmental disorder caused by deletions 22q13.3 or pathogenic variants in the SHANK3 gene. Lymphedema can be a clinical feature in 10-25% of individuals with PMS due to a deletion 22q13.3, but is not observed in those with a SHANK3 variant. This paper forms a part of the European consensus guideline for PMS and focuses on what is known regarding lymphedema in PMS in order to present clinical recommendations.