Objective: The aims of the study were to compare the stromal immunostaining of smooth muscle alpha-actin (α-SMA) and fibroblast activation protein-α (FAP) between borderline ovarian tumors and epithelial ovarian cancer, and to evaluate their association in overall survival (OS) and disease-free survival (DFS) in patients with ovarian cancer. Methods: Patients diagnosed with malignant (n = 28) and borderline ovarian tumors (n = 18) were evaluated. Immunohistochemical study of stromal α-SMA and FAP was carried out. The comparison of immunostaining between borderline and malignant ovarian tumors was performed using Fisher's exact test. Survival was assessed by the Kaplan-Meier method and the log-rank test. Multivariate analysis was performed by Cox regression. The differences were considered significant for p < 0.05. Results: Evaluating stromal FAP, stronger immunostaining (2 and 3) was more often found in epithelial ovarian cancer than in borderline ovarian tumors (p = 0.0331). There was no statistical significance in the assessment of α-SMA. Evaluating only patients with epithelial ovarian cancer, there was a higher OS in patients with stromal α-SMA immunostaining 3 (p = 0.017). There was no statistical significance when evaluating OS and DFS in patients with stromal FAP immunostaining, nor evaluating DFS in patients with α-SMA stromal immunostaining 3. After multivariate analysis, patients with stromal α-SMA immunostaining 3 had higher OS compared to immunostaining 0, 1 or 2 [OR (95% CI) = 0.107 (0.018–0.649), p = 0.015]. Conclusion: Stronger FAP immunostaining was more often found in epithelial ovarian cancer than in borderline ovarian tumors. In epithelial ovarian cancer, there was a higher OS in patients with stromal α-SMA immunostaining 3.