diff --git a/src/DemaConsulting.SpdxTool/SelfValidation/Validate.cs b/src/DemaConsulting.SpdxTool/SelfValidation/Validate.cs
index f6d10ee..7ddd118 100644
--- a/src/DemaConsulting.SpdxTool/SelfValidation/Validate.cs
+++ b/src/DemaConsulting.SpdxTool/SelfValidation/Validate.cs
@@ -62,6 +62,7 @@ public static void Run(Context context)
         ValidateCopyPackage.Run(context, results);
         ValidateFindPackage.Run(context, results);
         ValidateGetVersion.Run(context, results);
+        ValidateNtia.Run(context, results);
         ValidateQuery.Run(context, results);
         ValidateRenameId.Run(context, results);
         ValidateUpdatePackage.Run(context, results);
diff --git a/src/DemaConsulting.SpdxTool/SelfValidation/ValidateNtia.cs b/src/DemaConsulting.SpdxTool/SelfValidation/ValidateNtia.cs
new file mode 100644
index 0000000..85db22f
--- /dev/null
+++ b/src/DemaConsulting.SpdxTool/SelfValidation/ValidateNtia.cs
@@ -0,0 +1,204 @@
+// Copyright (c) 2024 DEMA Consulting
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+using DemaConsulting.TestResults;
+
+namespace DemaConsulting.SpdxTool.SelfValidation;
+
+/// <summary>
+///     Self-validation of NTIA validation
+/// </summary>
+internal static class ValidateNtia
+{
+    /// <summary>
+    ///     Run validation test
+    /// </summary>
+    /// <param name="context">Program context</param>
+    /// <param name="results">Test results</param>
+    public static void Run(Context context, TestResults.TestResults results)
+    {
+        var passed = DoValidate();
+
+        // Report validation result
+        context.WriteLine($"- SpdxTool_Ntia: {(passed ? "Passed" : "Failed")}");
+        results.Results.Add(
+            new TestResult
+            {
+                Name = "SpdxTool_Ntia",
+                ClassName = "DemaConsulting.SpdxTool.SelfValidation.ValidateNtia",
+                ComputerName = Environment.MachineName,
+                StartTime = DateTime.Now,
+                Outcome = passed ? TestOutcome.Passed : TestOutcome.Failed
+            });
+    }
+
+    /// <summary>
+    ///     Do the validation
+    /// </summary>
+    /// <returns>True on success</returns>
+    private static bool DoValidate()
+    {
+        try
+        {
+            // Create the temporary validation folder
+            Directory.CreateDirectory("validate.tmp");
+
+            // Run individual validation tests
+            return DoValidateMissingSupplier() && DoValidateCompliant();
+        }
+        finally
+        {
+            // Delete the temporary validation folder
+            Directory.Delete("validate.tmp", true);
+        }
+    }
+
+    /// <summary>
+    ///     Validate that NTIA validation detects missing supplier
+    /// </summary>
+    /// <returns>True on success</returns>
+    private static bool DoValidateMissingSupplier()
+    {
+        // Write test SPDX file that is valid but not NTIA compliant
+        // Missing: supplier field for the package
+        File.WriteAllText("validate.tmp/test-ntia.spdx.json",
+            """
+            {
+              "files": [],
+              "packages": [
+                {
+                  "SPDXID": "SPDXRef-Package",
+                  "name": "Test Package",
+                  "versionInfo": "1.0.0",
+                  "downloadLocation": "https://github.com/demaconsulting/SpdxTool",
+                  "filesAnalyzed": false,
+                  "licenseConcluded": "MIT"
+                }
+              ],
+              "relationships": [
+                {
+                  "spdxElementId": "SPDXRef-DOCUMENT",
+                  "relatedSpdxElement": "SPDXRef-Package",
+                  "relationshipType": "DESCRIBES"
+                }
+              ],
+              "spdxVersion": "SPDX-2.2",
+              "dataLicense": "CC0-1.0",
+              "SPDXID": "SPDXRef-DOCUMENT",
+              "name": "Test Document",
+              "documentNamespace": "https://sbom.spdx.org",
+              "creationInfo": {
+                "created": "2021-10-01T00:00:00Z",
+                "creators": [ "Person: Malcolm Nixon" ]
+              }
+            }
+            """);
+
+        // Run validation without NTIA flag - should succeed
+        var exitCode1 = Validate.RunSpdxTool(
+            "validate.tmp",
+            [
+                "--silent",
+                "validate",
+                "test-ntia.spdx.json"
+            ]);
+
+        // Fail if SpdxTool reported an error
+        if (exitCode1 != 0)
+            return false;
+
+        // Run validation with NTIA flag - should fail due to missing supplier
+        // The log file will be written to validate.tmp/output.log since the working directory is changed
+        var exitCode2 = Validate.RunSpdxTool(
+            "validate.tmp",
+            [
+                "--log", "output.log",
+                "validate",
+                "test-ntia.spdx.json",
+                "ntia"
+            ]);
+
+        // Should fail validation
+        if (exitCode2 == 0)
+            return false;
+
+        // Read the log file and verify it contains the expected error
+        var log = File.ReadAllText("validate.tmp/output.log");
+        if (!log.Contains("NTIA: Package 'Test Package' Missing Supplier"))
+            return false;
+
+        return true;
+    }
+
+    /// <summary>
+    ///     Validate that NTIA validation passes for compliant document
+    /// </summary>
+    /// <returns>True on success</returns>
+    private static bool DoValidateCompliant()
+    {
+        // Write test SPDX file that is NTIA compliant
+        File.WriteAllText("validate.tmp/test-ntia-valid.spdx.json",
+            """
+            {
+              "files": [],
+              "packages": [
+                {
+                  "SPDXID": "SPDXRef-Package",
+                  "name": "Test Package",
+                  "versionInfo": "1.0.0",
+                  "supplier": "Organization: Test",
+                  "downloadLocation": "https://github.com/demaconsulting/SpdxTool",
+                  "filesAnalyzed": false,
+                  "licenseConcluded": "MIT"
+                }
+              ],
+              "relationships": [
+                {
+                  "spdxElementId": "SPDXRef-DOCUMENT",
+                  "relatedSpdxElement": "SPDXRef-Package",
+                  "relationshipType": "DESCRIBES"
+                }
+              ],
+              "spdxVersion": "SPDX-2.2",
+              "dataLicense": "CC0-1.0",
+              "SPDXID": "SPDXRef-DOCUMENT",
+              "name": "Test Document",
+              "documentNamespace": "https://sbom.spdx.org",
+              "creationInfo": {
+                "created": "2021-10-01T00:00:00Z",
+                "creators": [ "Person: Malcolm Nixon" ]
+              }
+            }
+            """);
+
+        // Run validation with NTIA flag on valid document - should succeed
+        var exitCode = Validate.RunSpdxTool(
+            "validate.tmp",
+            [
+                "--silent",
+                "validate",
+                "test-ntia-valid.spdx.json",
+                "ntia"
+            ]);
+
+        // Should pass validation
+        return exitCode == 0;
+    }
+}
diff --git a/test/DemaConsulting.SpdxTool.Tests/SelfValidationTests.cs b/test/DemaConsulting.SpdxTool.Tests/SelfValidationTests.cs
index 37d04b1..8f96a9e 100644
--- a/test/DemaConsulting.SpdxTool.Tests/SelfValidationTests.cs
+++ b/test/DemaConsulting.SpdxTool.Tests/SelfValidationTests.cs
@@ -98,12 +98,13 @@ public void SelfValidation_TrxResults()
             Assert.Contains("SpdxTool_CopyPackage", results);
             Assert.Contains("SpdxTool_FindPackage", results);
             Assert.Contains("SpdxTool_GetVersion", results);
+            Assert.Contains("SpdxTool_Ntia", results);
             Assert.Contains("SpdxTool_Query", results);
             Assert.Contains("SpdxTool_RenameId", results);
             Assert.Contains("SpdxTool_UpdatePackage", results);
             Assert.Contains("""
                                              <ResultSummary outcome="Completed">
-                                               <Counters total="8" executed="8" passed="8" failed="0" />
+                                               <Counters total="9" executed="9" passed="9" failed="0" />
                                              </ResultSummary>
                                            """, results);
         }