diff --git a/lib/active_reporting/dimension.rb b/lib/active_reporting/dimension.rb
index 16135c6..7fbcea0 100644
--- a/lib/active_reporting/dimension.rb
+++ b/lib/active_reporting/dimension.rb
@@ -34,7 +34,8 @@ def type
     #
     # @return [Boolean]
     def datetime?
-      @datetime ||= type == TYPES[:degenerate] && model.column_for_attribute(@name).type == :datetime
+      col_type = model.column_for_attribute(@name).type
+      @datetime ||= type == TYPES[:degenerate] && %i[datetime date].include?(col_type)
     end
 
     # Tells if the dimension is hierarchical
diff --git a/test/active_reporting/report_test.rb b/test/active_reporting/report_test.rb
index e62d056..8f6837b 100644
--- a/test/active_reporting/report_test.rb
+++ b/test/active_reporting/report_test.rb
@@ -32,6 +32,29 @@ def test_report_runs_with_an_aggregate_other_than_count
     assert data.all? { |r| r.key?('a_metric') }
   end
 
+  def test_report_runs_with_a_year_grouping
+    if ENV['DB'] == 'pg'
+      metric = ActiveReporting::Metric.new(
+        :a_metric,
+        fact_model: UserFactModel,
+        dimensions: [{birthday_on: :year}]
+      )
+      report = ActiveReporting::Report.new(metric)
+      data = report.run
+      assert data.all? { |r| r.key?('birthday_on_year') }
+      assert data.size == 5
+    else
+      assert_raises ActiveReporting::InvalidDimensionLabel do
+        metric = ActiveReporting::Metric.new(
+          :a_metric,
+          fact_model: UserFactModel,
+          dimensions: [{birthday_on: :year}]
+        )
+        report = ActiveReporting::Report.new(metric)
+      end
+    end
+  end
+
   def test_report_runs_with_a_date_grouping
     if ENV['DB'] == 'pg'
       metric = ActiveReporting::Metric.new(:a_metric, fact_model: UserFactModel, dimensions: [{created_at: :month}])
diff --git a/test/fact_models.rb b/test/fact_models.rb
index e81f755..31a973a 100644
--- a/test/fact_models.rb
+++ b/test/fact_models.rb
@@ -39,6 +39,7 @@ class DateDimensionFactModel < ActiveReporting::FactModel
 
 class UserFactModel < ActiveReporting::FactModel
   default_dimension_label :username
+  dimension :birthday_on
   dimension :created_at
 end
 
diff --git a/test/schema.rb b/test/schema.rb
index 39b72ef..7905e03 100644
--- a/test/schema.rb
+++ b/test/schema.rb
@@ -57,6 +57,7 @@
 
   create_table :users, force: true do |t|
     t.string :username
+    t.date :birthday_on
     t.timestamps null: false
   end
 
diff --git a/test/seed.rb b/test/seed.rb
index 7d53e20..6905acb 100644
--- a/test/seed.rb
+++ b/test/seed.rb
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 (Date.new(2014,1,1)..Date.new(2017,12,31)).each do |d|
   DateDimension.new_from_date(d).save!
 end
@@ -5,6 +6,7 @@
 (1..5).each do |i|
   user = User.create!(
     created_at: Time.now - i.months,
+    birthday_on: (10 + i).years.ago ,
     username: "user_#{i}"
   )