BACKGROUND: Mantle cell lymphoma (MCL) is an aggressive subtype of B-cell non-Hodgkin's lymphoma. The applicability of circulating tumor DNA (ctDNA) for predicting treatment response and prognosis in MCL remains underexplored. METHODS: This study included 34 MCL patients receiving first-line chemoimmunotherapy. We assessed the ability of plasma ctDNA to detect tumor-specific genetic alterations and explored its potential as a noninvasive biomarker for treatment response and prognosis in MCL. RESULTS: Commonly mutated genes in MCL included CCND1 (93.5%), ATM (48.4%), KMT2D (25.8%), and TP53 (25.8%). Subgroup analysis of tissue samples showed that CDKN2A mutations (P = 0.028), along with alterations in BCR and TCR signaling (P = 0.004) and the PI3K pathway (P = 0.008), were enriched in the blastoid subtype. ATM mutations (P = 0.041) were more prevalent in MIPI-low patients, while epigenetic chromatin remodeling pathway alterations (P = 0.028) were more common in MIPI-high patients. Plasma ctDNA demonstrated high sensitivity for detecting structural variants (96.6%), followed by mutations (71.3%) and copy number variants (30.0%). 75% of patients exhibited moderate-to-high concordance in detecting genomic variants between plasma and tissue samples. Pretreatment ctDNA levels exhibited high specificity in predicting clinical efficacy but had a suboptimal sensitivity of 68.2%. Higher ctDNA levels were significantly associated with shorter progression-free survival (PFS; P = 0.002) and overall survival (OS; P = 0.009). Additional ctDNA-based genetic features associated with shorter PFS included TP53 (P = 0.002), TRAF2 (P = 0.023), and SMARCA4 (P = 0.023) mutations, while TP53 (P = 0.006) and TERT (P = 0.031) mutations predicted shorter OS. Persistent positive ctDNA in post-treatment plasma samples indicated molecular relapse and poor prognosis, whereas undetectable ctDNA defined a subset of patients with favorable survival outcomes. CONCLUSIONS: This study identified plasma ctDNA as a promising biomarker that noninvasively captures tumor-derived genetic variants associated with treatment response and survival outcomes in MCL, highlighting the clinical value of ctDNA for diagnosis, recurrence prediction, and surveillance monitoring.