diff --git a/packages/netlify-cms-core/src/actions/__tests__/config.spec.js b/packages/netlify-cms-core/src/actions/__tests__/config.spec.js
index 91ec0334..e1d42e3c 100644
--- a/packages/netlify-cms-core/src/actions/__tests__/config.spec.js
+++ b/packages/netlify-cms-core/src/actions/__tests__/config.spec.js
@@ -214,7 +214,7 @@ describe('config', () => {
           ).toEqual('static/images/docs');
         });
 
-        it('should not overwrite collection public_folder if set', () => {
+        it('should not overwrite collection public_folder if set to non empty string', () => {
           expect(
             applyDefaults({
               collections: [
@@ -229,6 +229,21 @@ describe('config', () => {
           ).toEqual('images/docs');
         });
 
+        it('should not overwrite collection public_folder if set to empty string', () => {
+          expect(
+            applyDefaults({
+              collections: [
+                {
+                  folder: 'foo',
+                  media_folder: 'static/images/docs',
+                  public_folder: '',
+                  fields: [{ name: 'title', widget: 'string' }],
+                },
+              ],
+            }).collections[0].public_folder,
+          ).toEqual('');
+        });
+
         it("should set collection media_folder and public_folder to an empty string when collection path exists, but collection media_folder doesn't", () => {
           const result = applyDefaults({
             collections: [
diff --git a/packages/netlify-cms-core/src/actions/config.ts b/packages/netlify-cms-core/src/actions/config.ts
index e8018d4b..985edd86 100644
--- a/packages/netlify-cms-core/src/actions/config.ts
+++ b/packages/netlify-cms-core/src/actions/config.ts
@@ -69,7 +69,7 @@ function getConfigUrl() {
 }
 
 function setDefaultPublicFolderForField<T extends CmsField>(field: T) {
-  if ('media_folder' in field && !field.public_folder) {
+  if ('media_folder' in field && !('public_folder' in field)) {
     return { ...field, public_folder: field.media_folder };
   }
   return field;
@@ -271,7 +271,7 @@ export function applyDefaults(originalConfig: CmsConfig) {
           collection.media_folder = '';
         }
 
-        if ('media_folder' in collection && !collection.public_folder) {
+        if ('media_folder' in collection && !('public_folder' in collection)) {
           collection.public_folder = collection.media_folder;
         }
 
@@ -303,7 +303,7 @@ export function applyDefaults(originalConfig: CmsConfig) {
         for (const file of files) {
           file.file = trimStart(file.file, '/');
 
-          if ('media_folder' in file && !file.public_folder) {
+          if ('media_folder' in file && !('public_folder' in file)) {
             file.public_folder = file.media_folder;
           }