diff --git a/lib/simple_form/form_builder.rb b/lib/simple_form/form_builder.rb
index 7680c6e5..e6b561f6 100644
--- a/lib/simple_form/form_builder.rb
+++ b/lib/simple_form/form_builder.rb
@@ -182,7 +182,9 @@ module SimpleForm
 
       options[:as] ||= :select
       options[:collection] ||= options.fetch(:collection) {
-        reflection.klass.where(reflection.options[:conditions]).order(reflection.options[:order]).to_a
+        conditions = reflection.options[:conditions]
+        conditions = conditions.call if conditions.is_a?(Proc)
+        reflection.klass.where(conditions).order(reflection.options[:order]).to_a
       }
 
       attribute = case reflection.macro