diff --git a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/SuppressibleMSBuildLog.cs b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/SuppressibleMSBuildLog.cs
index 0dda7cfe46cc..57e2ff4748cf 100644
--- a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/SuppressibleMSBuildLog.cs
+++ b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/SuppressibleMSBuildLog.cs
@@ -10,7 +10,8 @@ namespace Microsoft.DotNet.ApiCompat.Task
     /// Class that can log Suppressions in an MSBuild task, by implementing MSBuildLog and ISuppressibleLog.
     /// </summary>
     internal sealed class SuppressibleMSBuildLog(NET.Build.Tasks.Logger log,
-        ISuppressionEngine suppressionEngine) : MSBuildLog(log), ISuppressibleLog
+        ISuppressionEngine suppressionEngine,
+        string? noWarn = null) : MSBuildLog(log, noWarn), ISuppressibleLog
     {
         /// <inheritdoc />
         public bool HasLoggedErrorSuppressions { get; private set; }
diff --git a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/ValidateAssembliesTask.cs b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/ValidateAssembliesTask.cs
index 650245dae575..424d81b4862a 100644
--- a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/ValidateAssembliesTask.cs
+++ b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/ValidateAssembliesTask.cs
@@ -132,7 +132,7 @@ public override bool Execute()
 
         protected override void ExecuteCore()
         {
-            SuppressibleMSBuildLog logFactory(ISuppressionEngine suppressionEngine) => new(Log, suppressionEngine);
+            SuppressibleMSBuildLog logFactory(ISuppressionEngine suppressionEngine) => new(Log, suppressionEngine, NoWarn);
             ValidateAssemblies.Run(logFactory,
                 GenerateSuppressionFile,
                 PreserveUnnecessarySuppressions,
diff --git a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/ValidatePackageTask.cs b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/ValidatePackageTask.cs
index b839ca1d4325..196d90c47272 100644
--- a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/ValidatePackageTask.cs
+++ b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Task/ValidatePackageTask.cs
@@ -140,7 +140,7 @@ public override bool Execute()
 
         protected override void ExecuteCore()
         {
-            SuppressibleMSBuildLog logFactory(ISuppressionEngine suppressionEngine) => new(Log, suppressionEngine);
+            SuppressibleMSBuildLog logFactory(ISuppressionEngine suppressionEngine) => new(Log, suppressionEngine, NoWarn);
             ValidatePackage.Run(logFactory,
                 GenerateSuppressionFile,
                 PreserveUnnecessarySuppressions,
diff --git a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Tool/Program.cs b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Tool/Program.cs
index cb248930e153..1cf403f061f1 100644
--- a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Tool/Program.cs
+++ b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Tool/Program.cs
@@ -196,7 +196,7 @@ static int Main(string[] args)
                 (string, string)[]? leftAssembliesTransformationPattern = parseResult.GetValue(leftAssembliesTransformationPatternOption);
                 (string, string)[]? rightAssembliesTransformationPattern = parseResult.GetValue(rightAssembliesTransformationPatternOption);
 
-                SuppressibleConsoleLog logFactory(ISuppressionEngine suppressionEngine) => new(suppressionEngine, verbosity);
+                SuppressibleConsoleLog logFactory(ISuppressionEngine suppressionEngine) => new(suppressionEngine, verbosity, noWarn);
                 int exitCode = ValidateAssemblies.Run(logFactory,
                     generateSuppressionFile,
                     preserveUnnecessarySuppressions,
@@ -320,7 +320,7 @@ static int Main(string[] args)
                 Dictionary<NuGetFramework, IEnumerable<string>>? baselinePackageAssemblyReferences = parseResult.GetValue(baselinePackageAssemblyReferencesOption);
                 string[]? baselinePackageFrameworksToIgnore = parseResult.GetValue(baselinePackageFrameworksToIgnoreOption);
 
-                SuppressibleConsoleLog logFactory(ISuppressionEngine suppressionEngine) => new(suppressionEngine, verbosity);
+                SuppressibleConsoleLog logFactory(ISuppressionEngine suppressionEngine) => new(suppressionEngine, verbosity, noWarn);
                 int exitCode = ValidatePackage.Run(logFactory,
                     generateSuppressionFile,
                     preserveUnnecessarySuppressions,
diff --git a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Tool/SuppressibleConsoleLog.cs b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Tool/SuppressibleConsoleLog.cs
index 4bda2be1f799..5d2222e45a58 100644
--- a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Tool/SuppressibleConsoleLog.cs
+++ b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompat.Tool/SuppressibleConsoleLog.cs
@@ -10,7 +10,8 @@ namespace Microsoft.DotNet.ApiCompat.Tool
     /// Class that can log Suppressions to the Console, by implementing ConsoleLog and ISuppressibleLog.
     /// </summary>
     internal sealed class SuppressibleConsoleLog(ISuppressionEngine suppressionEngine,
-        MessageImportance messageImportance) : ConsoleLog(messageImportance), ISuppressibleLog
+        MessageImportance messageImportance,
+        string? noWarn = null) : ConsoleLog(messageImportance, noWarn), ISuppressibleLog
     {
         /// <inheritdoc />
         public bool HasLoggedErrorSuppressions { get; private set; }
diff --git a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompatibility/Logging/SuppressionEngine.cs b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompatibility/Logging/SuppressionEngine.cs
index fef506d21bbf..8fbfbc69c1ae 100644
--- a/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompatibility/Logging/SuppressionEngine.cs
+++ b/src/Compatibility/ApiCompat/Microsoft.DotNet.ApiCompatibility/Logging/SuppressionEngine.cs
@@ -17,7 +17,7 @@ public class SuppressionEngine(string? noWarn = null, bool baselineAllErrors = f
         protected const string DiagnosticIdDocumentationComment = " https://learn.microsoft.com/dotnet/fundamentals/package-validation/diagnostic-ids ";
         private readonly HashSet<Suppression> _baselineSuppressions = [];
         private readonly HashSet<Suppression> _suppressions = [];
-        private readonly HashSet<string> _noWarn = string.IsNullOrEmpty(noWarn) ? [] : new(noWarn!.Split(';'));
+        private readonly HashSet<string> _noWarn = string.IsNullOrEmpty(noWarn) ? [] : new(noWarn!.Split(';'), StringComparer.OrdinalIgnoreCase);
 
         /// <inheritdoc/>
         public bool BaselineAllErrors { get; } = baselineAllErrors;
diff --git a/src/Compatibility/Microsoft.DotNet.ApiSymbolExtensions/Logging/ConsoleLog.cs b/src/Compatibility/Microsoft.DotNet.ApiSymbolExtensions/Logging/ConsoleLog.cs
index fd380e6c1214..41754fadcfa2 100644
--- a/src/Compatibility/Microsoft.DotNet.ApiSymbolExtensions/Logging/ConsoleLog.cs
+++ b/src/Compatibility/Microsoft.DotNet.ApiSymbolExtensions/Logging/ConsoleLog.cs
@@ -6,8 +6,10 @@ namespace Microsoft.DotNet.ApiSymbolExtensions.Logging
     /// <summary>
     /// Class to define common logging abstraction to the console across the APICompat and GenAPI codebases.
     /// </summary>
-    public class ConsoleLog(MessageImportance messageImportance) : ILog
+    public class ConsoleLog(MessageImportance messageImportance, string? noWarn = null) : ILog
     {
+        private readonly HashSet<string> _noWarn = string.IsNullOrEmpty(noWarn) ? [] : new(noWarn!.Split(';'), StringComparer.OrdinalIgnoreCase);
+
         /// <inheritdoc />
         public bool HasLoggedErrors { get; private set; }
 
@@ -30,8 +32,20 @@ public virtual void LogWarning(string message) =>
             Console.WriteLine(message);
 
         /// <inheritdoc />
-        public virtual void LogWarning(string code, string message) =>
-            Console.WriteLine($"{code}: {message}");
+        public virtual void LogWarning(string code, string message)
+        {
+            string messageTextWithCode = $"{code}: {message}";
+
+            // Mimic MSBuild which logs suppressed warnings as low importance messages.
+            if (_noWarn.Contains(code))
+            {
+                LogMessage(MessageImportance.Low, messageTextWithCode);
+            }
+            else
+            {
+                Console.WriteLine(messageTextWithCode);
+            }
+        }
 
         /// <inheritdoc />
         public virtual void LogMessage(string message) =>
diff --git a/src/Compatibility/Microsoft.DotNet.ApiSymbolExtensions/Logging/MSBuildLog.cs b/src/Compatibility/Microsoft.DotNet.ApiSymbolExtensions/Logging/MSBuildLog.cs
index 2d85e521ecad..cd2eb8e5bc05 100644
--- a/src/Compatibility/Microsoft.DotNet.ApiSymbolExtensions/Logging/MSBuildLog.cs
+++ b/src/Compatibility/Microsoft.DotNet.ApiSymbolExtensions/Logging/MSBuildLog.cs
@@ -8,8 +8,11 @@ namespace Microsoft.DotNet.ApiSymbolExtensions.Logging
     /// <summary>
     /// Class to define common logging abstraction for MSBuild tasks across the APICompat and GenAPI codebases.
     /// </summary>
-    internal class MSBuildLog(Logger log) : ILog
+    internal class MSBuildLog(Logger log, string? noWarn = null) : ILog
     {
+        // Remove passing in NoWarn when MSBuild respects it correctly in outer-builds: https://github.com/dotnet/msbuild/issues/10873
+        private readonly HashSet<string> _noWarn = string.IsNullOrEmpty(noWarn) ? [] : new(noWarn!.Split(';'), StringComparer.OrdinalIgnoreCase);
+
         /// <inheritdoc />
         public bool HasLoggedErrors => log.HasLoggedErrors;
 
@@ -27,7 +30,8 @@ public virtual void LogWarning(string message) =>
 
         /// <inheritdoc />
         public virtual void LogWarning(string code, string message) =>
-            LogCore(MessageLevel.Warning, code, message);
+            // Mimic MSBuild which logs suppressed warnings as low importance messages.
+            LogCore(_noWarn.Contains(code) ? MessageLevel.LowImportance : MessageLevel.Warning, code, message);
 
         /// <inheritdoc />
         public virtual void LogMessage(string message) =>