diff --git a/pkg/generator/secret_template_reconciler.go b/pkg/generator/secret_template_reconciler.go
index 6e96f02c7..dddb4d4ed 100644
--- a/pkg/generator/secret_template_reconciler.go
+++ b/pkg/generator/secret_template_reconciler.go
@@ -6,6 +6,7 @@ package generator
 import (
 	"context"
 	"encoding/base64"
+	"encoding/json"
 	"fmt"
 	"time"
 
@@ -283,7 +284,12 @@ func evaluateTemplate(template *sg2v1alpha1.JSONPathTemplate, values map[string]
 	}
 
 	// Template Secret StringData
-	stringData, err := evaluate(template.StringData, values)
+	decodedValues, err := decodeSecrets(values)
+	if err != nil {
+		return corev1.Secret{}, fmt.Errorf("decoding secrets: %w", err)
+	}
+
+	stringData, err := evaluate(template.StringData, decodedValues)
 	if err != nil {
 		return corev1.Secret{}, fmt.Errorf("templating stringData: %w", err)
 	}
@@ -349,3 +355,34 @@ func evaluateBytes(mapping map[string]string, values map[string]interface{}) (ma
 
 	return evaluatedMapping, nil
 }
+
+func decodeSecrets(values map[string]interface{}) (map[string]interface{}, error) {
+	decodedValues := make(map[string]interface{})
+	for valueKey, value := range values {
+		jsonData, err := json.Marshal(value)
+		if err != nil {
+			return nil, fmt.Errorf("failed to marshal values into JSON: %w", err)
+		}
+
+		obj := &unstructured.Unstructured{}
+		if err := json.Unmarshal(jsonData, obj); err != nil {
+			return nil, fmt.Errorf("failed to unmarshal JSON into Unstructured object: %w", err)
+		}
+
+		if obj.GetKind() == "Secret" {
+			data, _, _ := unstructured.NestedStringMap(obj.Object, "data")
+			for dataKey, encodedValue := range data {
+				decodedValue, err := base64.StdEncoding.DecodeString(string(encodedValue))
+				if err != nil {
+					return nil, fmt.Errorf("failed decoding base64 from a Secret: %w", err)
+				}
+				unstructured.SetNestedStringMap(obj.Object, map[string]string{dataKey: string(decodedValue)}, "data")
+			}
+			decodedValues[valueKey] = obj.Object
+		} else {
+			decodedValues[valueKey] = value
+		}
+	}
+
+	return decodedValues, nil
+}
diff --git a/pkg/generator/secret_template_test.go b/pkg/generator/secret_template_test.go
index a24eed5ff..52f7458c8 100644
--- a/pkg/generator/secret_template_test.go
+++ b/pkg/generator/secret_template_test.go
@@ -89,6 +89,62 @@ func Test_SecretTemplate(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "reconciling secret template with input from another secret decoded in stringData",
+			template: sg2v1alpha1.SecretTemplate{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "secretTemplate",
+					Namespace: "test",
+				},
+				Spec: sg2v1alpha1.SecretTemplateSpec{
+					InputResources: []sg2v1alpha1.InputResource{{
+						Name: "creds",
+						Ref: sg2v1alpha1.InputResourceRef{
+							APIVersion: "v1",
+							Kind:       "Secret",
+							Name:       "existingSecret",
+						},
+					}},
+					JSONPathTemplate: &sg2v1alpha1.JSONPathTemplate{
+						Data: map[string]string{
+							"key1": "$( .creds.data.inputKey1 )",
+							"key2": "$( .creds.data.inputKey2 )",
+						},
+						StringData: map[string]string{
+							"key3": "test-$( .creds.data.inputKey3 )",
+						},
+					},
+				},
+			},
+			existingObjects: []client.Object{
+				secret("existingSecret", map[string]string{
+					"inputKey1": "value1",
+					"inputKey2": "value2",
+					"inputKey3": "value3",
+				}),
+			},
+			expectedSecret: corev1.Secret{
+				TypeMeta: metav1.TypeMeta{
+					Kind:       "Secret",
+					APIVersion: "v1",
+				},
+				ObjectMeta: metav1.ObjectMeta{
+					Name:            "secretTemplate",
+					Namespace:       "test",
+					ResourceVersion: "1",
+					OwnerReferences: []metav1.OwnerReference{
+						secretTemplateOwnerRef("secretTemplate"),
+					},
+				},
+				Data: map[string][]byte{
+					"key1": []byte("value1"),
+					"key2": []byte("value2"),
+				},
+				StringData: map[string]string{
+					"key3": "test-value3",
+				},
+			},
+		},
 		{
 			name: "reconciling secret template with input from two inputs with dynamic inputname",
 			template: sg2v1alpha1.SecretTemplate{