diff --git a/lib/openhab/core/items/group_function.rb b/lib/openhab/core/items/group_function.rb
new file mode 100644
index 0000000000..840846c254
--- /dev/null
+++ b/lib/openhab/core/items/group_function.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module OpenHAB
+  module Core
+    module Items
+      java_import org.openhab.core.items.GroupFunction
+
+      #
+      # Adds `#to_s` and `#inspect` to group function.
+      #
+      # @example
+      #   # Group:SWITCH:OR(ON,OFF) Switches
+      #   logger.info "The Switches group function is: #{Switches.function}" # => "OR"
+      #   logger.info "The Switches group function: #{Switches.function.inspect}" # => "OR(ON,OFF)"
+      #
+      module GroupFunction
+        #
+        # Returns the group function as an uppercase string
+        # @return [String]
+        #
+        def to_s
+          self.class.simple_name.upcase
+        end
+
+        #
+        # Returns the group function and its parameters as a string
+        # @return [String]
+        #
+        def inspect
+          params = parameters.map(&:inspect).join(",")
+          params = "(#{params})" unless params.empty?
+          "#{self}#{params}"
+        end
+      end
+    end
+  end
+end
diff --git a/lib/openhab/core/items/group_item.rb b/lib/openhab/core/items/group_item.rb
index 9641a3f1fa..5993133deb 100644
--- a/lib/openhab/core/items/group_item.rb
+++ b/lib/openhab/core/items/group_item.rb
@@ -149,10 +149,7 @@ def format_type(command)
         def type_details
           r = ""
           r += ":#{base_item.type}#{base_item.__send__(:type_details)}" if base_item
-          if function && (fn = function.class.java_class.simple_name.upcase) != "EQUALITY"
-            r += ":#{fn}"
-            r += "(#{function.parameters.map(&:inspect).join(",")})" unless function.parameters.empty?
-          end
+          r += ":#{function.inspect}" if function && function.to_s != "EQUALITY"
           r
         end
 
diff --git a/spec/openhab/core/items/group_item_spec.rb b/spec/openhab/core/items/group_item_spec.rb
index ffd5e7e3b1..9424b682c6 100644
--- a/spec/openhab/core/items/group_item_spec.rb
+++ b/spec/openhab/core/items/group_item_spec.rb
@@ -4,7 +4,7 @@
   before do
     items.build do
       group_item "Sensors" do
-        group_item "Temperatures"
+        group_item "Temperatures", type: :number, function: "AVG"
       end
 
       group_item "House" do
@@ -64,6 +64,23 @@
     end
   end
 
+  describe "#function" do
+    describe "#to_s" do
+      it "returns the function name in uppercase" do
+        expect(Temperatures.function.to_s).to eql "AVG"
+      end
+    end
+
+    describe "#inspect" do
+      it "includes the parameters" do
+        items.build do
+          group_item "Switches", type: :switch, function: "OR(ON,OFF)"
+        end
+        expect(Switches.function.inspect).to eql "OR(ON,OFF)"
+      end
+    end
+  end
+
   describe "#command" do
     it "propagates to all items" do
       GroundFloor.command(60)