diff --git a/schema/bom-1.5.proto b/schema/bom-1.5.proto
index d99c1a9c..5e177a5d 100644
--- a/schema/bom-1.5.proto
+++ b/schema/bom-1.5.proto
@@ -1009,6 +1009,8 @@ message ModelCard {
   optional QuantitativeAnalysis quantitativeAnalysis = 3;
   // What considerations should be taken into account regarding the model's construction, training, and application?
   optional ModelCardConsiderations considerations = 4;
+  // Specifies optional, custom, properties
+  repeated Property properties = 5;
 
   message ModelParameters {
     // The overall approach to learning used by the model for problem solving.
diff --git a/schema/bom-1.5.xsd b/schema/bom-1.5.xsd
index 0651bcdd..cf00327e 100644
--- a/schema/bom-1.5.xsd
+++ b/schema/bom-1.5.xsd
@@ -22,7 +22,7 @@ limitations under the License.
            targetNamespace="http://cyclonedx.org/schema/bom/1.5"
            vc:minVersion="1.0"
            vc:maxVersion="1.1"
-           version="1.5.0">
+           version="1.5.1">
 
     <xs:import namespace="http://cyclonedx.org/schema/spdx" schemaLocation="http://cyclonedx.org/schema/spdx"/>
 
@@ -3008,6 +3008,16 @@ limitations under the License.
                     </xs:sequence>
                 </xs:complexType>
             </xs:element>
+            <xs:element name="properties" type="bom:propertiesType" minOccurs="0" maxOccurs="1">
+                <xs:annotation>
+                    <xs:documentation>Provides the ability to document properties in a name/value store.
+                        This provides flexibility to include data not officially supported in the standard
+                        without having to use additional namespaces or create extensions. Property names
+                        of interest to the general public are encouraged to be registered in the
+                        CycloneDX Property Taxonomy - https://github.com/CycloneDX/cyclonedx-property-taxonomy.
+                        Formal registration is OPTIONAL.</xs:documentation>
+                </xs:annotation>
+            </xs:element>
         </xs:sequence>
         <xs:attribute name="bom-ref" type="bom:refType">
             <xs:annotation>
diff --git a/schema/bom-1.6.proto b/schema/bom-1.6.proto
index ddcfc3f7..23d48f3f 100644
--- a/schema/bom-1.6.proto
+++ b/schema/bom-1.6.proto
@@ -1152,6 +1152,8 @@ message ModelCard {
   optional QuantitativeAnalysis quantitativeAnalysis = 3;
   // What considerations should be taken into account regarding the model's construction, training, and application?
   optional ModelCardConsiderations considerations = 4;
+  // Specifies optional, custom, properties
+  repeated Property properties = 5;
 
   message ModelParameters {
     // The overall approach to learning used by the model for problem-solving.
diff --git a/schema/bom-1.6.xsd b/schema/bom-1.6.xsd
index 847c5261..cda59559 100644
--- a/schema/bom-1.6.xsd
+++ b/schema/bom-1.6.xsd
@@ -22,7 +22,7 @@ limitations under the License.
            targetNamespace="http://cyclonedx.org/schema/bom/1.6"
            vc:minVersion="1.0"
            vc:maxVersion="1.1"
-           version="1.6.1">
+           version="1.6.2">
 
     <xs:import namespace="http://cyclonedx.org/schema/spdx" schemaLocation="http://cyclonedx.org/schema/spdx"/>
 
@@ -3386,6 +3386,16 @@ limitations under the License.
                     </xs:sequence>
                 </xs:complexType>
             </xs:element>
+            <xs:element name="properties" type="bom:propertiesType" minOccurs="0" maxOccurs="1">
+                <xs:annotation>
+                    <xs:documentation>Provides the ability to document properties in a name/value store.
+                        This provides flexibility to include data not officially supported in the standard
+                        without having to use additional namespaces or create extensions. Property names
+                        of interest to the general public are encouraged to be registered in the
+                        CycloneDX Property Taxonomy - https://github.com/CycloneDX/cyclonedx-property-taxonomy.
+                        Formal registration is OPTIONAL.</xs:documentation>
+                </xs:annotation>
+            </xs:element>
         </xs:sequence>
         <xs:attribute name="bom-ref" type="bom:refType">
             <xs:annotation>
diff --git a/schema/bom-1.7.proto b/schema/bom-1.7.proto
index 6def360f..93b08538 100644
--- a/schema/bom-1.7.proto
+++ b/schema/bom-1.7.proto
@@ -1254,6 +1254,8 @@ message ModelCard {
   optional QuantitativeAnalysis quantitativeAnalysis = 3;
   // What considerations should be taken into account regarding the model's construction, training, and application?
   optional ModelCardConsiderations considerations = 4;
+  // Specifies optional, custom, properties
+  repeated Property properties = 5;
 
   message ModelParameters {
     // The overall approach to learning used by the model for problem-solving.
diff --git a/schema/bom-1.7.xsd b/schema/bom-1.7.xsd
index deba3de2..c84b2e08 100644
--- a/schema/bom-1.7.xsd
+++ b/schema/bom-1.7.xsd
@@ -22,7 +22,7 @@ limitations under the License.
            targetNamespace="http://cyclonedx.org/schema/bom/1.7"
            vc:minVersion="1.0"
            vc:maxVersion="1.1"
-           version="1.7.0">
+           version="1.7.1">
 
     <xs:import namespace="http://cyclonedx.org/schema/spdx" schemaLocation="http://cyclonedx.org/schema/spdx"/>
 
@@ -3629,6 +3629,16 @@ limitations under the License.
                     </xs:sequence>
                 </xs:complexType>
             </xs:element>
+            <xs:element name="properties" type="bom:propertiesType" minOccurs="0" maxOccurs="1">
+                <xs:annotation>
+                    <xs:documentation>Provides the ability to document properties in a name/value store.
+                        This provides flexibility to include data not officially supported in the standard
+                        without having to use additional namespaces or create extensions. Property names
+                        of interest to the general public are encouraged to be registered in the
+                        CycloneDX Property Taxonomy - https://github.com/CycloneDX/cyclonedx-property-taxonomy.
+                        Formal registration is OPTIONAL.</xs:documentation>
+                </xs:annotation>
+            </xs:element>
         </xs:sequence>
         <xs:attribute name="bom-ref" type="bom:refType">
             <xs:annotation>
diff --git a/tools/src/test/resources/1.5/valid-machine-learning-1.5.json b/tools/src/test/resources/1.5/valid-machine-learning-1.5.json
index 59dc3cee..58f5572a 100644
--- a/tools/src/test/resources/1.5/valid-machine-learning-1.5.json
+++ b/tools/src/test/resources/1.5/valid-machine-learning-1.5.json
@@ -85,7 +85,13 @@
               "mitigationStrategy": "With respect to the benefits and harms outlined, please describe any mitigation strategy implemented."
             }
           ]
-        }
+        },
+        "properties": [
+          {
+            "name": "modelcard:custom-property",
+            "value": "custom-value"
+          }
+        ]
       }
     }
   ]
diff --git a/tools/src/test/resources/1.5/valid-machine-learning-1.5.textproto b/tools/src/test/resources/1.5/valid-machine-learning-1.5.textproto
index 4e54321d..42887baa 100644
--- a/tools/src/test/resources/1.5/valid-machine-learning-1.5.textproto
+++ b/tools/src/test/resources/1.5/valid-machine-learning-1.5.textproto
@@ -62,5 +62,9 @@ components {
         mitigationStrategy: "With respect to the benefits and harms outlined, please describe any mitigation strategy implemented."
       }
     }
+    properties: {
+      name: "modelcard:custom-property"
+      value: "custom-value"
+    }
   }
 }
diff --git a/tools/src/test/resources/1.5/valid-machine-learning-1.5.xml b/tools/src/test/resources/1.5/valid-machine-learning-1.5.xml
index 7c541ecb..946d0c8f 100644
--- a/tools/src/test/resources/1.5/valid-machine-learning-1.5.xml
+++ b/tools/src/test/resources/1.5/valid-machine-learning-1.5.xml
@@ -86,6 +86,9 @@
                         </fairnessAssessment>
                     </fairnessAssessments>
                 </considerations>
+                <properties>
+                    <property name="modelcard:custom-property">custom-value</property>
+                </properties>
             </modelCard>
         </component>
     </components>
diff --git a/tools/src/test/resources/1.6/valid-machine-learning-1.6.json b/tools/src/test/resources/1.6/valid-machine-learning-1.6.json
index dbd0ea7b..df09c03c 100644
--- a/tools/src/test/resources/1.6/valid-machine-learning-1.6.json
+++ b/tools/src/test/resources/1.6/valid-machine-learning-1.6.json
@@ -87,7 +87,13 @@
               "mitigationStrategy": "With respect to the benefits and harms outlined, please describe any mitigation strategy implemented."
             }
           ]
-        }
+        },
+        "properties": [
+          {
+            "name": "modelcard:custom-property",
+            "value": "custom-value"
+          }
+        ]
       }
     }
   ]
diff --git a/tools/src/test/resources/1.6/valid-machine-learning-1.6.textproto b/tools/src/test/resources/1.6/valid-machine-learning-1.6.textproto
index 54452d65..3a1456e6 100644
--- a/tools/src/test/resources/1.6/valid-machine-learning-1.6.textproto
+++ b/tools/src/test/resources/1.6/valid-machine-learning-1.6.textproto
@@ -77,5 +77,9 @@ components {
         mitigationStrategy: "With respect to the benefits and harms outlined, please describe any mitigation strategy implemented."
       }
     }
+    properties: {
+      name: "modelcard:custom-property"
+      value: "custom-value"
+    }
   }
 }
diff --git a/tools/src/test/resources/1.6/valid-machine-learning-1.6.xml b/tools/src/test/resources/1.6/valid-machine-learning-1.6.xml
index 6013b1c3..f44f6179 100644
--- a/tools/src/test/resources/1.6/valid-machine-learning-1.6.xml
+++ b/tools/src/test/resources/1.6/valid-machine-learning-1.6.xml
@@ -86,6 +86,9 @@
                         </fairnessAssessment>
                     </fairnessAssessments>
                 </considerations>
+                <properties>
+                    <property name="modelcard:custom-property">custom-value</property>
+                </properties>
             </modelCard>
         </component>
     </components>
diff --git a/tools/src/test/resources/1.7/valid-machine-learning-1.7.json b/tools/src/test/resources/1.7/valid-machine-learning-1.7.json
index cb64ee80..e7a26820 100644
--- a/tools/src/test/resources/1.7/valid-machine-learning-1.7.json
+++ b/tools/src/test/resources/1.7/valid-machine-learning-1.7.json
@@ -95,7 +95,13 @@
               "mitigationStrategy": "With respect to the benefits and harms outlined, please describe any mitigation strategy implemented."
             }
           ]
-        }
+        },
+        "properties": [
+          {
+            "name": "modelcard:custom-property",
+            "value": "custom-value"
+          }
+        ]
       }
     }
   ]
diff --git a/tools/src/test/resources/1.7/valid-machine-learning-1.7.textproto b/tools/src/test/resources/1.7/valid-machine-learning-1.7.textproto
index 25b78f5d..818de8f5 100644
--- a/tools/src/test/resources/1.7/valid-machine-learning-1.7.textproto
+++ b/tools/src/test/resources/1.7/valid-machine-learning-1.7.textproto
@@ -76,5 +76,9 @@ components: {
         mitigationStrategy: "With respect to the benefits and harms outlined, please describe any mitigation strategy implemented."
       }
     }
+    properties: {
+      name: "modelcard:custom-property"
+      value: "custom-value"
+    }
   }
 }
diff --git a/tools/src/test/resources/1.7/valid-machine-learning-1.7.xml b/tools/src/test/resources/1.7/valid-machine-learning-1.7.xml
index 38df43ff..34305ef9 100644
--- a/tools/src/test/resources/1.7/valid-machine-learning-1.7.xml
+++ b/tools/src/test/resources/1.7/valid-machine-learning-1.7.xml
@@ -88,6 +88,9 @@
                         </fairnessAssessment>
                     </fairnessAssessments>
                 </considerations>
+                <properties>
+                    <property name="modelcard:custom-property">custom-value</property>
+                </properties>
             </modelCard>
         </component>
     </components>