diff --git a/lib/simple_form/inputs/collection_input.rb b/lib/simple_form/inputs/collection_input.rb
index 975bee1a..1ac15de1 100644
--- a/lib/simple_form/inputs/collection_input.rb
+++ b/lib/simple_form/inputs/collection_input.rb
@@ -105,11 +105,13 @@ module SimpleForm
       def translate_option(options, key)
         return unless options[key].is_a? Symbol
 
+        namespace = key.to_s.pluralize
+
         options[key] = case options[key]
         when :translate, :t
-          translate(key, true)
+          translate(namespace, true)
         else
-          I18n.t(options[key], scope: :"simple_form.#{key}")
+          I18n.t(options[key], scope: :"simple_form.#{namespace}")
         end
       end
     end
diff --git a/test/inputs/collection_select_input_test.rb b/test/inputs/collection_select_input_test.rb
index 252b2fd0..3c736a64 100644
--- a/test/inputs/collection_select_input_test.rb
+++ b/test/inputs/collection_select_input_test.rb
@@ -97,7 +97,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should translate include blank when set to :translate' do
-    store_translations(:en, :simple_form => { :include_blank => { :user => {
+    store_translations(:en, :simple_form => { :include_blanks => { :user => {
       :age => 'Rather not say'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :include_blank => :translate
@@ -106,7 +106,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should translate include blank when set to :t' do
-    store_translations(:en, :simple_form => { :include_blank => { :user => {
+    store_translations(:en, :simple_form => { :include_blanks => { :user => {
       :age => 'Rather not say'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :include_blank => :t
@@ -115,7 +115,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should translate include blank with a particular key' do
-    store_translations(:en, :simple_form => { :include_blank => {
+    store_translations(:en, :simple_form => { :include_blanks => {
       :age => 'Rather not say',
       :user => { :age => 'Should be overridden' }
     } } ) do
@@ -125,7 +125,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should not translate include blank when set to a string' do
-    store_translations(:en, :simple_form => { :include_blank => { :user => {
+    store_translations(:en, :simple_form => { :include_blanks => { :user => {
       :age => 'Rather not say'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :include_blank => 'Young at heart'
@@ -134,7 +134,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should not translate include blank when automatically set' do
-    store_translations(:en, :simple_form => { :include_blank => { :user => {
+    store_translations(:en, :simple_form => { :include_blanks => { :user => {
       :age => 'Rather not say'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30
@@ -143,7 +143,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should not translate include blank when set to true' do
-    store_translations(:en, :simple_form => { :include_blank => { :user => {
+    store_translations(:en, :simple_form => { :include_blanks => { :user => {
       :age => 'Rather not say'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :include_blank => true
@@ -152,7 +152,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should not translate include blank when set to false' do
-    store_translations(:en, :simple_form => { :include_blank => { :user => {
+    store_translations(:en, :simple_form => { :include_blanks => { :user => {
       :age => 'Rather not say'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :include_blank => false
@@ -176,7 +176,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should translate prompt when set to :translate' do
-    store_translations(:en, :simple_form => { :prompt => { :user => {
+    store_translations(:en, :simple_form => { :prompts => { :user => {
       :age => 'Select age:'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :prompt => :translate
@@ -185,7 +185,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should translate prompt when set to :t' do
-    store_translations(:en, :simple_form => { :prompt => { :user => {
+    store_translations(:en, :simple_form => { :prompts => { :user => {
       :age => 'Select age:'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :prompt => :t
@@ -194,7 +194,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should translate prompt with a particular key' do
-    store_translations(:en, :simple_form => { :prompt => {
+    store_translations(:en, :simple_form => { :prompts => {
       :age => 'Select age:',
       :user => { :age => 'Should be overridden' }
     } } ) do
@@ -204,7 +204,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should not translate prompt when set to a string' do
-    store_translations(:en, :simple_form => { :prompt => { :user => {
+    store_translations(:en, :simple_form => { :prompts => { :user => {
       :age => 'Select age:'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :prompt => 'Do it:'
@@ -213,7 +213,7 @@ class CollectionSelectInputTest < ActionView::TestCase
   end
 
   test 'input should not translate prompt when set to false' do
-    store_translations(:en, :simple_form => { :prompt => { :user => {
+    store_translations(:en, :simple_form => { :prompts => { :user => {
       :age => 'Select age:'
     } } } ) do
       with_input_for @user, :age, :select, :collection => 18..30, :prompt => false