White mulberry (Morus alba L.) leaves are traditionally used to support glycemic control in diabetic and prediabetic individuals; however, their physiological effects in the context of hypertension remain poorly defined. This study investigated the effects of dietary supplementation with dried, powdered mulberry leaves (ML) on hematological indices and splenic redox biomarkers in spontaneously hypertensive rats (SHRs). Middle–aged male SHRs (n = 10 rats) were fed either standard rat chow or chow supplemented with dried ML (7% w/w; ~4.0 g kg-1 body weight) for eight weeks. Hematological parameters were assessed from the whole blood, and antioxidant and inflammatory markers in spleen homogenates were quantified. ML supplementation increased hematocrit (HCT; 1.05–fold, p = 0.0206), mean corpuscular volume (MCV; 1.01–fold, p = 0.0013), and total white blood cell count (WBC; 1.56–fold, p = 0.0128), while decreasing mean corpuscular hemoglobin concentration (MCHC; 0.99–fold, p = 0.0192). In splenic tissue, DPPH scavenging activity and protein levels of PTGS1, NOS2, NOS3, HO–1, and GAPDH remained unchanged, whereas ferric–reducing antioxidant power (FRAP) was significantly reduced (0.75–fold, p = 0.0014). No significant alterations were observed in body weight change (p = 0.999), feed consumption (p = 0.676), or relative spleen weights (p = 0.798). Dietary dried, powdered ML supplementation elicits measurable alterations in hematological parameters and attenuates splenic antioxidant capacity in SHRs, indicating that ML may modulate hematological parameters and spleen redox homeostasis in hypertension.