diff --git a/lib/appenders/file.js b/lib/appenders/file.js
index 73dad71..673e348 100644
--- a/lib/appenders/file.js
+++ b/lib/appenders/file.js
@@ -29,6 +29,8 @@ function mainSighupHandler() {
 function fileAppender(file, layout, logSize, numBackups, options, timezoneOffset) {
   if (typeof file !== "string" || file.length === 0) {
     throw new Error(`Invalid filename: ${file}`);
+  } else if (file.endsWith(path.sep)) {
+    throw new Error(`Filename is a directory: ${file}`);
   }
   file = path.normalize(file);
   numBackups = (!numBackups && numBackups !== 0) ? 5 : numBackups;
diff --git a/lib/appenders/fileSync.js b/lib/appenders/fileSync.js
index 7519de5..24b3f9a 100755
--- a/lib/appenders/fileSync.js
+++ b/lib/appenders/fileSync.js
@@ -164,6 +164,8 @@ class RollingFileSync {
 function fileAppender(file, layout, logSize, numBackups, options, timezoneOffset) {
   if (typeof file !== "string" || file.length === 0) {
     throw new Error(`Invalid filename: ${file}`);
+  } else if (file.endsWith(path.sep)) {
+    throw new Error(`Filename is a directory: ${file}`);
   }
   file = path.normalize(file);
   numBackups = (!numBackups && numBackups !== 0) ? 5 : numBackups;
diff --git a/test/tap/fileAppender-test.js b/test/tap/fileAppender-test.js
index 5ca1f6a..ebc298b 100644
--- a/test/tap/fileAppender-test.js
+++ b/test/tap/fileAppender-test.js
@@ -50,7 +50,6 @@ test("log4js fileAppender", batch => {
 
   batch.test("should give error if invalid filename", async t => {
     const file = "";
-    const expectedError = new Error(`Invalid filename: ${file}`);
     t.throws(
       () => 
         log4js.configure({
@@ -64,7 +63,23 @@ test("log4js fileAppender", batch => {
             default: { appenders: ["file"], level: "debug" }
           }
         }),
-      expectedError
+      new Error(`Invalid filename: ${file}`)
+    );
+    const dir = `.${path.sep}`;
+    t.throws(
+      () => 
+        log4js.configure({
+          appenders: {
+            file: {
+              type: "file",
+              filename: dir
+            }
+          },
+          categories: {
+            default: { appenders: ["file"], level: "debug" }
+          }
+        }),
+      new Error(`Filename is a directory: ${dir}`)
     );
     t.end();
   });
diff --git a/test/tap/fileSyncAppender-test.js b/test/tap/fileSyncAppender-test.js
index b36e3b0..4ea96ac 100644
--- a/test/tap/fileSyncAppender-test.js
+++ b/test/tap/fileSyncAppender-test.js
@@ -78,7 +78,6 @@ test("log4js fileSyncAppender", batch => {
 
   batch.test("should give error if invalid filename", async t => {
     const file = "";
-    const expectedError = new Error(`Invalid filename: ${file}`);
     t.throws(
       () => 
         log4js.configure({
@@ -92,7 +91,23 @@ test("log4js fileSyncAppender", batch => {
             default: { appenders: ["file"], level: "debug" }
           }
         }),
-      expectedError
+      new Error(`Invalid filename: ${file}`)
+    );
+    const dir = `.${path.sep}`;
+    t.throws(
+      () => 
+        log4js.configure({
+          appenders: {
+            file: {
+              type: "fileSync",
+              filename: dir
+            }
+          },
+          categories: {
+            default: { appenders: ["file"], level: "debug" }
+          }
+        }),
+      new Error(`Filename is a directory: ${dir}`)
     );
     t.end();
   });