diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1203fafc36..f2b2a3c6b3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 #### Features
 * Your contribution here.
+* [#2018](https://github.com/ruby-grape/grape/pull/2018): Avoid coercing parameter with multiple types to an empty Array - [@stanhu](https://github.com/stanhu).
 * [#2015](https://github.com/ruby-grape/grape/pull/2014): Reduce MatchData allocation - [@ericproulx](https://github.com/ericproulx).
 * [#2014](https://github.com/ruby-grape/grape/pull/2014): Reduce total allocated arrays - [@ericproulx](https://github.com/ericproulx).
 * [#2011](https://github.com/ruby-grape/grape/pull/2011): Reduce total retained regexes - [@ericproulx](https://github.com/ericproulx).
diff --git a/lib/grape/validations/validators/coerce.rb b/lib/grape/validations/validators/coerce.rb
index 561ec1bcf2..fcad312b53 100644
--- a/lib/grape/validations/validators/coerce.rb
+++ b/lib/grape/validations/validators/coerce.rb
@@ -68,9 +68,10 @@ def coerce_value(val)
         # define default values for structures, the dry-types lib which is used
         # for coercion doesn't accept nil as a value, so it would fail
         if val.nil?
-          return []      if type == Array || type.is_a?(Array)
+          return []      if type == Array
           return Set.new if type == Set
           return {}      if type == Hash
+          return val     if type.is_a?(Array)
         end
 
         converter.call(val)
diff --git a/spec/grape/validations/validators/coerce_spec.rb b/spec/grape/validations/validators/coerce_spec.rb
index dbf57c9d57..cb2cca5f95 100644
--- a/spec/grape/validations/validators/coerce_spec.rb
+++ b/spec/grape/validations/validators/coerce_spec.rb
@@ -647,6 +647,19 @@ def self.parsed?(value)
         expect(last_response.body).to eq('String')
       end
 
+      it 'respects nil values' do
+        subject.params do
+          optional :a, types: [File, String]
+        end
+        subject.get '/' do
+          params[:a].class.to_s
+        end
+
+        get '/', a: nil
+        expect(last_response.status).to eq(200)
+        expect(last_response.body).to eq('NilClass')
+      end
+
       it 'fails when no coercion is possible' do
         subject.params do
           requires :a, types: [Boolean, Integer]