diff --git a/data-prepper-plugins/parse-json-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessor.java b/data-prepper-plugins/parse-json-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessor.java
index e076b7de10..a2f5ad2ea4 100644
--- a/data-prepper-plugins/parse-json-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessor.java
+++ b/data-prepper-plugins/parse-json-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessor.java
@@ -40,6 +40,7 @@ public class ParseJsonProcessor extends AbstractProcessor<Record<Event>, Record<
     private final String pointer;
     private final String parseWhen;
     private final List<String> tagsOnFailure;
+    private final boolean overwriteIfKeyExists;
 
     private final ExpressionEvaluator expressionEvaluator;
 
@@ -54,6 +55,7 @@ public ParseJsonProcessor(final PluginMetrics pluginMetrics,
         pointer = parseJsonProcessorConfig.getPointer();
         parseWhen = parseJsonProcessorConfig.getParseWhen();
         tagsOnFailure = parseJsonProcessorConfig.getTagsOnFailure();
+        overwriteIfKeyExists = parseJsonProcessorConfig.getOverwriteIfKeyExists();
         this.expressionEvaluator = expressionEvaluator;
     }
 
@@ -85,7 +87,7 @@ public Collection<Record<Event>> doExecute(final Collection<Record<Event>> recor
 
                     if (doWriteToRoot) {
                         writeToRoot(event, parsedJson);
-                    } else {
+                    } else if (overwriteIfKeyExists || !event.containsKey(destination)) {
                         event.put(destination, parsedJson);
                     }
                 } catch (final JsonProcessingException jsonException) {
@@ -169,7 +171,9 @@ private String trimPointer(String pointer) {
 
     private void writeToRoot(final Event event, final Map<String, Object> parsedJson) {
         for (Map.Entry<String, Object> entry : parsedJson.entrySet()) {
-            event.put(entry.getKey(), entry.getValue());
+            if (overwriteIfKeyExists || !event.containsKey(entry.getKey())) {
+                event.put(entry.getKey(), entry.getValue());
+            }
         }
     }
 }
diff --git a/data-prepper-plugins/parse-json-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorConfig.java b/data-prepper-plugins/parse-json-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorConfig.java
index fa6dbe199b..ae49c07596 100644
--- a/data-prepper-plugins/parse-json-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorConfig.java
+++ b/data-prepper-plugins/parse-json-processor/src/main/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorConfig.java
@@ -31,6 +31,9 @@ public class ParseJsonProcessorConfig {
     @JsonProperty("tags_on_failure")
     private List<String> tagsOnFailure;
 
+    @JsonProperty("overwrite_if_key_exists")
+    private boolean overwriteIfKeyExists = true;
+
     /**
      * The field of the Event that contains the JSON data.
      *
@@ -68,6 +71,10 @@ public List<String> getTagsOnFailure() {
 
     public String getParseWhen() { return parseWhen; }
 
+    public boolean getOverwriteIfKeyExists() {
+        return overwriteIfKeyExists;
+    }
+
     @AssertTrue(message = "destination cannot be empty, whitespace, or a front slash (/)")
     boolean isValidDestination() {
         if (Objects.isNull(destination)) return true;
diff --git a/data-prepper-plugins/parse-json-processor/src/test/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorConfigTest.java b/data-prepper-plugins/parse-json-processor/src/test/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorConfigTest.java
index ea3ef5a7f7..4012f7a848 100644
--- a/data-prepper-plugins/parse-json-processor/src/test/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorConfigTest.java
+++ b/data-prepper-plugins/parse-json-processor/src/test/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorConfigTest.java
@@ -29,6 +29,7 @@ public void test_when_defaultParseJsonProcessorConfig_then_returns_default_value
         assertThat(objectUnderTest.getDestination(), equalTo(null));
         assertThat(objectUnderTest.getPointer(), equalTo(null));
         assertThat(objectUnderTest.getTagsOnFailure(), equalTo(null));
+        assertThat(objectUnderTest.getOverwriteIfKeyExists(), equalTo(true));
     }
 
     @Nested
diff --git a/data-prepper-plugins/parse-json-processor/src/test/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorTest.java b/data-prepper-plugins/parse-json-processor/src/test/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorTest.java
index 7fce6ecbe5..123f1f44bc 100644
--- a/data-prepper-plugins/parse-json-processor/src/test/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorTest.java
+++ b/data-prepper-plugins/parse-json-processor/src/test/java/org/opensearch/dataprepper/plugins/processor/parsejson/ParseJsonProcessorTest.java
@@ -52,6 +52,7 @@ void setup() {
         when(processorConfig.getDestination()).thenReturn(defaultConfig.getDestination());
         when(processorConfig.getPointer()).thenReturn(defaultConfig.getPointer());
         when(processorConfig.getParseWhen()).thenReturn(null);
+        when(processorConfig.getOverwriteIfKeyExists()).thenReturn(true);
     }
 
     private ParseJsonProcessor createObjectUnderTest() {
@@ -94,6 +95,42 @@ void test_when_dataFieldEqualToRootField_then_overwritesOriginalFields() {
         assertThatKeyEquals(parsedEvent, "key", "value");
     }
 
+    @Test
+    void test_when_dataFieldEqualToRootField_then_notOverwritesOriginalFields() {
+        final String source = "root_source";
+        when(processorConfig.getSource()).thenReturn(source);
+        when(processorConfig.getOverwriteIfKeyExists()).thenReturn(false);
+        parseJsonProcessor = createObjectUnderTest(); // need to recreate so that new config options are used
+
+        final Map<String, Object> data = Map.ofEntries(
+                entry(source,"value_that_will_overwrite_source"),
+                entry("key","value")
+        );
+
+        final String serializedMessage = convertMapToJSONString(data);
+        final Event parsedEvent = createAndParseMessageEvent(serializedMessage);
+
+        assertThatKeyEquals(parsedEvent, source, "{\"root_source\":\"value_that_will_overwrite_source\", \"key\":\"value\"}");
+        assertThatKeyEquals(parsedEvent, "key", "value");
+    }
+
+    @Test
+    void test_when_dataFieldEqualToDestinationField_then_notOverwritesOriginalFields() {
+        final String source = "root_source";
+        when(processorConfig.getSource()).thenReturn(source);
+        when(processorConfig.getDestination()).thenReturn(source);  // write back to source
+        when(processorConfig.getOverwriteIfKeyExists()).thenReturn(false);
+        parseJsonProcessor = createObjectUnderTest(); // need to recreate so that new config options are used
+
+        final Map<String, Object> data = Map.of("key","value");
+
+        final String serializedMessage = convertMapToJSONString(data);
+        final Event parsedEvent = createAndParseMessageEvent(serializedMessage);
+
+        assertThatKeyEquals(parsedEvent, source, "{\"key\":\"value\"}");
+        assertThat(parsedEvent.containsKey("key"), equalTo(false));
+    }
+
     @Test
     void test_when_valueIsEmpty_then_notParsed() {
         parseJsonProcessor = createObjectUnderTest();