Alterations of the Hippo–YAP pathway are potential targets for oral squamous cell carcinoma (OSCC) therapy, but heterogeneity in this pathway could be responsible for therapeutic resistance. We analysed the Hippo–YAP signatures in a cohort of characterised keratinocyte cell lines derived from the mouth floor and buccal mucosa from different stages of OSCC tumour progression and focused on the specific role of YAP on invasive and metastatic potential. We confirmed heterogeneity in the Hippo–YAP pathway in OSCC lines, including overexpression of YAP1, WWTR1 (often referred to as TAZ) and the major Hippo signalling components, as well as the variations in the genes encoding the intercellular anchoring junctional proteins, which could potentially regulate the Hippo pathway. Specifically, desmoglein‐3 (DSG3) exhibited a unique and mutually exclusive regulation of YAP via YAP phosphorylation during the collective migration of OSCC cells. Mechanistically, such regulation was associated with inhibition of phosphorylation of epidermal growth factor receptor (EGFR) (S695/Y1086) and its downstream effectors heat shock protein beta‐1 (Hsp27) (S78/S82) and transcription factor AP‐1 (c‐Jun) (S63), leading to YAP phosphorylation coupled with its cytoplasmic translocation and inactivation. Additionally, OSCC lines displayed distinct phenotypes of YAP dependency or a mixed YAP and TAZ dependency for cell migration and present distinct patterns in YAP abundance and activity, with the latter being associated with YAP nuclear localisation. In conclusion, this study provides evidence for a newly identified paradigm in the Hippo–YAP pathway and suggests a new regulation mechanism involved in the control of collective migration in OSCC cells. Here, we investigated the reciprocal regulation between DSG3 and YAP in oral squamous cell carcinoma (OSCC) cells. We observed that low DSG3 expression was coupled with activation of YAP, which was predominantly located in the nucleus, via EGFR signalling. In contrast, in cells expressing high levels of DSG3, YAP was phosphorylated and translocated to the cytoplasm, via inhibition of EGFR signalling. Altogether, high DSG3 levels lead to contact inhibition of cell locomotion, and attenuated collective cell migration of OSCC cells.