Lung cancer is an intrinsically highly metastatic disease and the leading cause of cancer-related deaths worldwide. Although discovery of molecular aberrations in lung adenocarcinomas has led to development of effective targeted therapies, corresponding “drivers” in lung squamous carcinomas (LUSC) have not materialized. Extensive molecular profiling has revealed LUSC tumors have non-recurrent somatic mutations and are largely driven by copy number alterations. Because microRNAs (miRs) play increasingly important roles in regulating metastasis-relevant pathways, we evaluated whether miRs can regulate LUSC progression. By integrating bioinformatics of the Cancer Genome Atlas (TCGA) with novel, highly metastatic LUSC models, we found that miR-671-5p is a key inhibitor of LUSC metastasis. Surprisingly, miR-671-5p regulates LUSC metastasis by inhibiting a circular RNA (circRNA), CDR1as. Although the putative function of CDR1as is through miR-7 sponging, we found miR-671-5p more potently silences an axis of CDR1as and its anti-sense transcript, cerebellar degeneration related antigen 1 (CDR1). To our knowledge, no function of CDR1 has ever been described. We found loss of CDR1as and CDR1 significantly inhibited LUSC metastases. Intriguingly, CDR1 was strongly associated with an epithelial-mesenchymal transition (EMT) program in LUSC tumors, and was sufficient to promote metastases, increased migration and substrate-independent survival, known as anoikis-resistance. CDR1, which directly interacts with AP1 and COPI subunits, no longer promoted migration and anoikis-resistance upon blockade of Golgi trafficking. Our findings reveal a miR/circRNA axis that regulates LUSC metastases through an enigmatic protein, CDR1.