diff --git a/docs/index.md b/docs/index.md
index d63d3d0cfe..f03365da7c 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -1970,6 +1970,8 @@ The JSON reporter outputs a single large JSON object when the tests have complet
 
 By default, it will output to the console. To write directly to a file, use `--reporter-option output=filename.json`.
 
+The indentation of the JSON reporter can be set with --reporter-option indentation=Number. Number being any integer. Alternatively, you can set the indentation to a tab character using --reporter-option indentation='\t'.
+
 ![json reporter](images/reporter-json.png?withoutEnlargement&resize=920,9999){:class="screenshot" loading="lazy"}
 
 ### JSON Stream
diff --git a/lib/reporters/json.js b/lib/reporters/json.js
index 993fa379f5..7dff11c5fe 100644
--- a/lib/reporters/json.js
+++ b/lib/reporters/json.js
@@ -78,14 +78,14 @@ function JSONReporter(runner, options = {}) {
 
     runner.testResults = obj;
 
-    options.indentation = options.reporterOption?.indentSize ?? 2; // Default indenation
+    const indentation = options.reporterOption?.indentation?? 2;
 
     var json;
 
-    if (options.indentation === '\\t') {
+    if (indentation === '\\t') {
       json = JSON.stringify(obj, null, '\t');
     } else {
-      json = JSON.stringify(obj, null, parseInt(options.indentation, 10));
+      json = JSON.stringify(obj, null, parseInt(indentation, 10));
     }
 
     if (output) {
diff --git a/test/reporters/json.spec.js b/test/reporters/json.spec.js
index a824a0419f..bcebca0b9b 100644
--- a/test/reporters/json.spec.js
+++ b/test/reporters/json.spec.js
@@ -230,7 +230,7 @@ describe('JSON reporter', function () {
       );
     });
 
-    it('should set options.indentation correctly', function () {
+    it('should set options.indentation with a number', function () {
       var options = {indentation: 4};
       var mochaReporter = new mocha._reporter(runner, options);