diff --git a/analytics/src/FirebaseAnalytics.cs b/analytics/src/FirebaseAnalytics.cs
index d3c600db9..e61bf24a6 100644
--- a/analytics/src/FirebaseAnalytics.cs
+++ b/analytics/src/FirebaseAnalytics.cs
@@ -15,11 +15,14 @@
  */
 
 using System.Threading.Tasks;
+using Firebase.Platform;
 
 namespace Firebase.Analytics {
 
 public static partial class FirebaseAnalytics {
 
+  private static readonly Firebase.Platform.ModuleLogger logger = new Firebase.Platform.ModuleLogger("FirebaseAnalytics");
+
   /// Get the instance ID from the analytics service.
   ///
   /// @returns A Task with the Analytics instance ID.
@@ -248,6 +251,61 @@ public static void SetConsent(System.Collections.Generic.IDictionary< ConsentTyp
     FirebaseAnalyticsInternal.SetConsentWithInts(consentSettingsMap);
   }
 
+  /// @brief Sets default event parameters.
+  ///
+  /// These parameters are logged with all events, in addition to the parameters passed to the
+  /// LogEvent() call. They are useful for logging common parameters with all events.
+  /// Default event parameters are overridden by event-specific parameters if the names are the
+  /// same. Default parameters are removed if the dictionary is null or empty.
+  ///
+  /// @param[in] parameters The dictionary of parameters to set.
+  ///   If null, clears all default parameters.
+  public static void SetDefaultEventParameters(
+      System.Collections.Generic.IDictionary<string, object> parameters) {
+    if (parameters == null) {
+      logger.LogMessage(LogLevel.Debug, "Input parameters dictionary is null. Clearing all default event parameters.");
+      FirebaseAnalyticsInternal.ClearDefaultEventParameters();
+    } else {
+      StringList parameterNames = new StringList();
+      VariantList parameterValues = new VariantList();
+
+      if (parameters.Count == 0) {
+        logger.LogMessage(LogLevel.Debug, "Input parameters dictionary is empty. Clearing all default event parameters via empty map.");
+        // Proceed with empty lists, C++ SDK will clear defaults when given an empty map.
+      } else {
+        logger.LogMessage(LogLevel.Debug, string.Format("Processing {0} default event parameter(s).", parameters.Count));
+        foreach (var kvp in parameters) {
+          try {
+            Firebase.Variant variantValue = Firebase.Variant.FromObject(kvp.Value);
+            // Assuming Variant.FromObject(null) correctly yields a Variant.Null()
+            // and doesn't throw for it, or that Variant.Null() is a valid state.
+            // If Variant.FromObject might return an "invalid" Variant object for certain inputs
+            // instead of throwing (e.g. for unsupported types that don't cause exceptions),
+            // an additional check like `if (!variantValue.IsValid())` might be needed here.
+            // For now, relying on try-catch for conversion failures.
+
+            parameterNames.Add(kvp.Key);
+            parameterValues.Add(variantValue);
+          } catch (System.Exception e) {
+            logger.LogMessage(LogLevel.Warning, string.Format(
+                "Failed to convert default parameter '{0}' (value type: {1}). Skipping. Error: {2}",
+                kvp.Key, kvp.Value?.GetType().FullName ?? "null", e.Message));
+          }
+        }
+      }
+
+      // If parameters.Count was > 0 but all failed conversion, parameterNames will be empty.
+      // Sending empty lists to C++ SetDefaultEventParameters (with map) results in clearing.
+      if (parameters.Count > 0 && parameterNames.Count == 0) {
+          logger.LogMessage(LogLevel.Warning, "All supplied default parameters failed conversion. This will result in clearing all default parameters.");
+      } else if (parameterNames.Count > 0) {
+          logger.LogMessage(LogLevel.Debug, string.Format("Setting {0} default event parameter(s) via helper.", parameterNames.Count));
+      }
+      // Always call SetDefaultEventParametersHelper. If lists are empty, it clears params.
+      FirebaseAnalyticsInternal.SetDefaultEventParametersHelper(parameterNames, parameterValues);
+    }
+  }
+
   /// @brief Sets the duration of inactivity that terminates the current session.
   ///
   /// @note The default value is 30 minutes.
diff --git a/analytics/src/swig/analytics.i b/analytics/src/swig/analytics.i
index 866f6d4fb..98579d4a5 100644
--- a/analytics/src/swig/analytics.i
+++ b/analytics/src/swig/analytics.i
@@ -87,6 +87,24 @@ void SetConsentWithInts(const std::map<int, int>& settings) {
   SetConsent(converted);
 }
 
+// Helper function to set default event parameters from vectors of strings and variants.
+void SetDefaultEventParametersHelper(
+    const std::vector<std::string>& parameter_names,
+    const std::vector<firebase::Variant>& parameter_values) {
+  if (parameter_names.size() != parameter_values.size()) {
+    firebase::LogError(
+        "SetDefaultEventParametersHelper given different list sizes (%d, %d)",
+        parameter_names.size(), parameter_values.size());
+    return;
+  }
+
+  std::map<std::string, firebase::Variant> default_parameters;
+  for (size_t i = 0; i < parameter_names.size(); ++i) {
+    default_parameters[parameter_names[i]] = parameter_values[i];
+  }
+  SetDefaultEventParameters(default_parameters);
+}
+
 }  // namespace analytics
 }  // namespace firebase
 
@@ -100,6 +118,8 @@ void SetConsentWithInts(const std::map<int, int>& settings) {
 %ignore firebase::analytics::LogEvent(const char*, const Parameter*, size_t);
 // Ignore SetConsent, in order to convert the types with our own function.
 %ignore firebase::analytics::SetConsent;
+// Ignore SetDefaultEventParameters, as we handle it with a custom helper.
+%ignore firebase::analytics::SetDefaultEventParameters;
 // Ignore the Parameter class, as we don't want to expose that to C# at all.
 %ignore firebase::analytics::Parameter;
 
@@ -121,5 +141,9 @@ namespace analytics {
 void LogEvent(const char* name, std::vector<std::string> parameter_names,
               std::vector<firebase::Variant> parameter_values);
 void SetConsentWithInts(const std::map<int, int>& settings);
+void SetDefaultEventParametersHelper(
+    const std::vector<std::string>& parameter_names,
+    const std::vector<firebase::Variant>& parameter_values);
+void ClearDefaultEventParameters();
 }  // namespace analytics
 }  // namespace firebase
diff --git a/analytics/testapp/Assets/Firebase/Sample/Analytics/UIHandler.cs b/analytics/testapp/Assets/Firebase/Sample/Analytics/UIHandler.cs
index 08564b79d..8e9198356 100644
--- a/analytics/testapp/Assets/Firebase/Sample/Analytics/UIHandler.cs
+++ b/analytics/testapp/Assets/Firebase/Sample/Analytics/UIHandler.cs
@@ -162,6 +162,32 @@ public void AnalyticsSetConsent() {
       });
     }
 
+    public void TestSetDefaultEventParameters() {
+      DebugLog("Starting TestSetDefaultEventParameters...");
+
+      DebugLog("Setting single default string parameter: {'default_param_string', 'default_value_1'}");
+      FirebaseAnalytics.SetDefaultEventParameters(new Dictionary<string, object>
+      {
+          { "default_param_string", "default_value_1" }
+      });
+
+      DebugLog("Setting multiple default parameters: {'default_param_int', 123, 'default_param_double', 45.67, 'default_param_bool', true}");
+      FirebaseAnalytics.SetDefaultEventParameters(new Dictionary<string, object>
+      {
+          { "default_param_int", 123 },
+          { "default_param_double", 45.67 },
+          { "default_param_bool", true }
+      });
+
+      DebugLog("Clearing default parameters with null.");
+      FirebaseAnalytics.SetDefaultEventParameters(null);
+
+      DebugLog("Clearing default parameters with empty dictionary.");
+      FirebaseAnalytics.SetDefaultEventParameters(new Dictionary<string, object>());
+
+      DebugLog("TestSetDefaultEventParameters completed.");
+    }
+
     // Get the current app instance ID.
     public Task<string> DisplayAnalyticsInstanceId() {
       return FirebaseAnalytics.GetAnalyticsInstanceIdAsync().ContinueWithOnMainThread(task => {
@@ -257,6 +283,9 @@ void GUIDisplayControls() {
         if (GUILayout.Button("Test SetConsent")) {
           AnalyticsSetConsent();
         }
+        if (GUILayout.Button("Test SetDefaultEventParameters")) {
+          TestSetDefaultEventParameters();
+        }
         GUILayout.EndVertical();
         GUILayout.EndScrollView();
       }
diff --git a/analytics/testapp/Assets/Firebase/Sample/Analytics/UIHandlerAutomated.cs b/analytics/testapp/Assets/Firebase/Sample/Analytics/UIHandlerAutomated.cs
index e101771ab..a32975844 100644
--- a/analytics/testapp/Assets/Firebase/Sample/Analytics/UIHandlerAutomated.cs
+++ b/analytics/testapp/Assets/Firebase/Sample/Analytics/UIHandlerAutomated.cs
@@ -40,6 +40,7 @@ public override void Start() {
         TestAnalyticsSetConsentDoesNotThrow,
         TestInstanceIdChangeAfterReset,
         TestResetAnalyticsData,
+        TestSetDefaultEventParametersAutomated, // Renamed test here
         // Temporarily disabled until this test is deflaked. b/143603151
         //TestCheckAndFixDependenciesInvalidOperation,
         TestCheckAndFixDependenciesDoubleCall,
@@ -108,6 +109,40 @@ Task TestAnalyticsSetConsentDoesNotThrow() {
         return true;
       });
     }
+
+    Task TestSetDefaultEventParametersAutomated() {
+      DebugLog("Automated Test: Starting TestSetDefaultEventParametersAutomated...");
+
+      DebugLog("Automated Test: Setting single default string parameter: {'auto_default_param_string', 'auto_value_1'}");
+      FirebaseAnalytics.SetDefaultEventParameters(new Dictionary<string, object>
+      {
+          { "auto_default_param_string", "auto_value_1" }
+      });
+
+      DebugLog("Automated Test: Setting multiple default parameters: {'auto_default_param_int', 789, 'auto_default_param_double', 12.34, 'auto_default_param_bool', false}");
+      FirebaseAnalytics.SetDefaultEventParameters(new Dictionary<string, object>
+      {
+          { "auto_default_param_int", 789 },
+          { "auto_default_param_double", 12.34 },
+          { "auto_default_param_bool", false }
+      });
+
+      DebugLog("Automated Test: Setting a default parameter with a null value: {'param_with_null_value', null}");
+      FirebaseAnalytics.SetDefaultEventParameters(new Dictionary<string, object>
+      {
+          { "param_with_null_value", null }
+      });
+
+      DebugLog("Automated Test: Clearing default parameters with null.");
+      FirebaseAnalytics.SetDefaultEventParameters(null);
+
+      DebugLog("Automated Test: Clearing default parameters with empty dictionary.");
+      FirebaseAnalytics.SetDefaultEventParameters(new Dictionary<string, object>());
+
+      DebugLog("Automated Test: TestSetDefaultEventParametersAutomated completed.");
+      return Task.FromResult(true); // Indicate successful completion
+    }
+
     Task TestCheckAndFixDependenciesInvalidOperation() {
       // Only run the test on Android, as CheckAndFixDependenciesAsync is short
       // lived on other platforms, and thus could finish before the extra call.