diff --git a/multiplatform/install_qt/action.yml b/multiplatform/install_qt/action.yml
index 07038af9..f9171d4d 100644
--- a/multiplatform/install_qt/action.yml
+++ b/multiplatform/install_qt/action.yml
@@ -24,6 +24,7 @@ inputs:
   modules:
     description: 'String with whitespace delimited list of additional addon modules to install'
     required: false
+    default: ''
 
   archives:
     description: 'String with whitespace delimited list of Qt archives to install, with each entry separated by a space'
@@ -45,6 +46,7 @@ inputs:
     description: 'Qt "tools" to be installed. Specify the tool name and tool variant name separated by commas,
      and separate multiple tools with spaces'
     required: false
+    default: ''
 
   add-tools-to-path:
     description: 'Tools path are included into PATH variable if set to true'
@@ -58,6 +60,7 @@ inputs:
     description: 'String with whitespace delimited list of source archives to install, with each entry separated by
      a space. Has no effect unless source is set to true'
     required: false
+    default: ''
 
   documentation:
     description: 'Set this to true to install Qt documentation files. Incompatible with aqtinstall < 2.0.4'
@@ -67,11 +70,13 @@ inputs:
     description: 'String with whitespace delimited list of documentation archives to install, with each entry separated
      by a space. Has no effect unless documentation is set to true'
     required: false
+    default: ''
 
   doc-modules:
     description: 'String with whitespace delimited list of documentation modules to install, with each entry separated
      by a space. Has no effect unless documentation is set to true'
     required: false
+    default: ''
 
   examples:
     description: 'Set this to true to install Qt example code. Incompatible with aqtinstall < 2.0.4'
@@ -81,11 +86,13 @@ inputs:
     description: 'String with whitespace delimited list of example archives to install, with each entry separated by
      a space. Has no effect unless examples is set to true'
     required: false
+    default: ''
 
   example-modules:
     description: 'String with whitespace delimited list of example modules to install, with each entry separated by
      a space. Has no effect unless examples is set to true'
     required: false
+    default: ''
 
   set-env:
     description: 'Avoid setting environment variables. Has no effect on tools paths'