diff --git a/data-prepper-plugins/mutate-string-processors/README.md b/data-prepper-plugins/mutate-string-processors/README.md
index 82d731ea27..8d72eebc87 100644
--- a/data-prepper-plugins/mutate-string-processors/README.md
+++ b/data-prepper-plugins/mutate-string-processors/README.md
@@ -88,7 +88,7 @@ If `from` substring does not have a match, the key will be returned as it is.
 ### Configuration
 * `entries` - (required) - A list of entries to add to an event
   * `source` - (required) - The key to be modified
-  * `from` - (required) - The substring to be replaced. This cannot be regex.
+  * `from` - (required) - The substring to be replaced. This doesn't support regex.
   * `to` - (required) - The String to be substituted for each match of `from`
 
 ---
diff --git a/data-prepper-plugins/mutate-string-processors/src/main/java/org/opensearch/dataprepper/plugins/processor/mutatestring/ReplaceStringProcessor.java b/data-prepper-plugins/mutate-string-processors/src/main/java/org/opensearch/dataprepper/plugins/processor/mutatestring/ReplaceStringProcessor.java
index adf3ec9f23..15ec8615db 100644
--- a/data-prepper-plugins/mutate-string-processors/src/main/java/org/opensearch/dataprepper/plugins/processor/mutatestring/ReplaceStringProcessor.java
+++ b/data-prepper-plugins/mutate-string-processors/src/main/java/org/opensearch/dataprepper/plugins/processor/mutatestring/ReplaceStringProcessor.java
@@ -30,10 +30,10 @@ public ReplaceStringProcessor(final PluginMetrics pluginMetrics, final ReplaceSt
         this.expressionEvaluator = expressionEvaluator;
 
         for(final ReplaceStringProcessorConfig.Entry entry : config.getEntries()) {
-            if (entry.getSubstituteWhen() != null
-                    && !expressionEvaluator.isValidExpressionStatement(entry.getSubstituteWhen())) {
+            if (entry.getReplaceWhen() != null
+                    && !expressionEvaluator.isValidExpressionStatement(entry.getReplaceWhen())) {
                 throw new InvalidPluginConfigurationException(
-                        String.format("substitute_when %s is not a valid expression statement. See https://opensearch.org/docs/latest/data-prepper/pipelines/expression-syntax/ for valid expression syntax", entry.getSubstituteWhen()));
+                        String.format("substitute_when %s is not a valid expression statement. See https://opensearch.org/docs/latest/data-prepper/pipelines/expression-syntax/ for valid expression syntax", entry.getReplaceWhen()));
             }
         }
     }
@@ -41,7 +41,7 @@ public ReplaceStringProcessor(final PluginMetrics pluginMetrics, final ReplaceSt
     @Override
     protected void performKeyAction(final Event recordEvent, final ReplaceStringProcessorConfig.Entry entry, final String value)
     {
-        if (Objects.nonNull(entry.getSubstituteWhen()) && !expressionEvaluator.evaluateConditional(entry.getSubstituteWhen(), recordEvent)) {
+        if (Objects.nonNull(entry.getReplaceWhen()) && !expressionEvaluator.evaluateConditional(entry.getReplaceWhen(), recordEvent)) {
             return;
         }
 
diff --git a/data-prepper-plugins/mutate-string-processors/src/main/java/org/opensearch/dataprepper/plugins/processor/mutatestring/ReplaceStringProcessorConfig.java b/data-prepper-plugins/mutate-string-processors/src/main/java/org/opensearch/dataprepper/plugins/processor/mutatestring/ReplaceStringProcessorConfig.java
index 091f3ab0c1..6d049910fb 100644
--- a/data-prepper-plugins/mutate-string-processors/src/main/java/org/opensearch/dataprepper/plugins/processor/mutatestring/ReplaceStringProcessorConfig.java
+++ b/data-prepper-plugins/mutate-string-processors/src/main/java/org/opensearch/dataprepper/plugins/processor/mutatestring/ReplaceStringProcessorConfig.java
@@ -22,14 +22,14 @@ public static class Entry {
         private EventKey source;
         @JsonPropertyDescription("The substring to be replaced in the source.")
         private String from;
-        @JsonPropertyDescription("The string to be substituted for each match of `from`.")
+        @JsonPropertyDescription("The string to be replaced for each match of `from`.")
         private String to;
 
-        @JsonProperty("substitute_when")
+        @JsonProperty("replace_when")
         @JsonPropertyDescription("A Data Prepper [conditional expression](https://opensearch.org/docs/latest/data-prepper/pipelines/expression-syntax/), " +
                 "such as `/some-key == \"test\"'`, that will be evaluated to determine whether the processor will be " +
                 "run on the event. Default is `null`. All events will be processed unless otherwise stated.")
-        private String substituteWhen;
+        private String replaceWhen;
 
         public EventKey getSource() {
             return source;
@@ -43,13 +43,13 @@ public String getTo() {
             return to;
         }
 
-        public String getSubstituteWhen() { return substituteWhen; }
+        public String getReplaceWhen() { return replaceWhen; }
 
-        public Entry(final EventKey source, final String from, final String to, final String substituteWhen) {
+        public Entry(final EventKey source, final String from, final String to, final String replaceWhen) {
             this.source = source;
             this.from = from;
             this.to = to;
-            this.substituteWhen = substituteWhen;
+            this.replaceWhen = replaceWhen;
         }
 
         public Entry() {}