Peritoneal surface malignancies (PSMs) are cancers that originate from the peritoneum, often spreading from other cancers such as colorectal, ovarian, and gastric cancers. Over the past two decades, improvements in treatment, including perioperative chemotherapy, cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy (HIPEC), have significantly improved outcomes. PSMs are characterized by a unique peritoneal microenvironment, where fibroblasts play a crucial role in tumor development, progression, and therapy resistance. Peritoneal metastasis-associated fibroblasts (MAFs) are highly heterogeneous, with immune-regulatory cancer-associated fibroblasts (iCAFs) being the most prevalent subtype. Other subtypes, such as myofibroblastic CAFs (myCAFs) and matrix CAFs (mCAFs), are also frequently observed. These fibroblasts originate from various sources, including mesothelial cells, submesothelial fibroblasts, pericytes, endothelial cells, and omental-resident cells. Their plasticity and heterogeneity contribute to the complex microenvironment of PSMs, impacting treatment responses. Understanding these interactions is crucial for developing targeted and local therapies to improve PSM patient outcomes. The study highlights the importance of fibroblasts in PSMs, their diverse origins, and their roles in tumor progression and therapy resistance. The findings suggest that the local microenvironment shapes MAFs, and further research is needed to better understand their origins and functions.Peritoneal surface malignancies (PSMs) are cancers that originate from the peritoneum, often spreading from other cancers such as colorectal, ovarian, and gastric cancers. Over the past two decades, improvements in treatment, including perioperative chemotherapy, cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy (HIPEC), have significantly improved outcomes. PSMs are characterized by a unique peritoneal microenvironment, where fibroblasts play a crucial role in tumor development, progression, and therapy resistance. Peritoneal metastasis-associated fibroblasts (MAFs) are highly heterogeneous, with immune-regulatory cancer-associated fibroblasts (iCAFs) being the most prevalent subtype. Other subtypes, such as myofibroblastic CAFs (myCAFs) and matrix CAFs (mCAFs), are also frequently observed. These fibroblasts originate from various sources, including mesothelial cells, submesothelial fibroblasts, pericytes, endothelial cells, and omental-resident cells. Their plasticity and heterogeneity contribute to the complex microenvironment of PSMs, impacting treatment responses. Understanding these interactions is crucial for developing targeted and local therapies to improve PSM patient outcomes. The study highlights the importance of fibroblasts in PSMs, their diverse origins, and their roles in tumor progression and therapy resistance. The findings suggest that the local microenvironment shapes MAFs, and further research is needed to better understand their origins and functions.