diff --git a/modules/openapi-generator/src/main/resources/ruby-client/model.mustache b/modules/openapi-generator/src/main/resources/ruby-client/model.mustache
index fa8f8c5bbb17..64eea20eaee1 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/model.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/model.mustache
@@ -17,8 +17,15 @@ module {{moduleName}}
 {{>partial_oneof_module}}
 {{/-first}}
 {{/oneOf}}
+{{#anyOf}}
+{{#-first}}
+{{>partial_anyof_module}}
+{{/-first}}
+{{/anyOf}}
 {{^oneOf}}
+{{^anyOf}}
 {{>partial_model_generic}}
+{{/anyOf}}
 {{/oneOf}}
 {{/isEnum}}
 {{/model}}
diff --git a/modules/openapi-generator/src/main/resources/ruby-client/model_test.mustache b/modules/openapi-generator/src/main/resources/ruby-client/model_test.mustache
index 99148c770a14..a3138fdee2a2 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/model_test.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/model_test.mustache
@@ -13,6 +13,7 @@ require 'date'
 {{#model}}
 describe {{moduleName}}::{{classname}} do
 {{^oneOf}}
+{{^anyOf}}
   let(:instance) { {{moduleName}}::{{classname}}.new }
 
   describe 'test an instance of {{classname}}' do
@@ -37,6 +38,7 @@ describe {{moduleName}}::{{classname}} do
   end
 
 {{/vars}}
+{{/anyOf}}
 {{/oneOf}}
 {{#oneOf}}
 {{#-first}}
diff --git a/modules/openapi-generator/src/main/resources/ruby-client/partial_anyof_module.mustache b/modules/openapi-generator/src/main/resources/ruby-client/partial_anyof_module.mustache
new file mode 100644
index 000000000000..ccd63dc0d85f
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/ruby-client/partial_anyof_module.mustache
@@ -0,0 +1,94 @@
+  {{#description}}
+  # {{{.}}}
+  {{/description}}
+  module {{classname}}
+    class << self
+      {{#anyOf}}
+      {{#-first}}
+      # List of class defined in anyOf (OpenAPI v3)
+      def openapi_any_of
+        [
+      {{/-first}}
+          :'{{{.}}}'{{^-last}},{{/-last}}
+      {{#-last}}
+        ]
+      end
+
+      {{/-last}}
+      {{/anyOf}}
+      # Builds the object
+      # @param [Mixed] Data to be matched against the list of anyOf items
+      # @return [Object] Returns the model or the data itself
+      def build(data)
+        # Go through the list of anyOf items and attempt to identify the appropriate one.
+        # Note:
+        # - No advanced validation of types in some cases (e.g. "x: { type: string }" will happily match { x: 123 })
+        #   due to the way the deserialization is made in the base_object template (it just casts without verifying).
+        # - TODO: scalar values are de facto behaving as if they were nullable.
+        # - TODO: logging when debugging is set.
+        openapi_any_of.each do |klass|
+          begin
+            next if klass == :AnyType # "nullable: true"
+            typed_data = find_and_cast_into_type(klass, data)
+            return typed_data if typed_data
+          rescue # rescue all errors so we keep iterating even if the current item lookup raises
+          end
+        end
+
+        openapi_any_of.include?(:AnyType) ? data : nil
+      end
+
+      private
+
+      SchemaMismatchError = Class.new(StandardError)
+
+      # Note: 'File' is missing here because in the regular case we get the data _after_ a call to JSON.parse.
+      def find_and_cast_into_type(klass, data)
+        return if data.nil?
+
+        case klass.to_s
+        when 'Boolean'
+          return data if data.instance_of?(TrueClass) || data.instance_of?(FalseClass)
+        when 'Float'
+          return data if data.instance_of?(Float)
+        when 'Integer'
+          return data if data.instance_of?(Integer)
+        when 'Time'
+          return Time.parse(data)
+        when 'Date'
+          return Date.parse(data)
+        when 'String'
+          return data if data.instance_of?(String)
+        when 'Object' # "type: object"
+          return data if data.instance_of?(Hash)
+        when /\AArray<(?<sub_type>.+)>\z/ # "type: array"
+          if data.instance_of?(Array)
+            sub_type = Regexp.last_match[:sub_type]
+            return data.map { |item| find_and_cast_into_type(sub_type, item) }
+          end
+        when /\AHash<String, (?<sub_type>.+)>\z/ # "type: object" with "additionalProperties: { ... }"
+          if data.instance_of?(Hash) && data.keys.all? { |k| k.instance_of?(Symbol) || k.instance_of?(String) }
+            sub_type = Regexp.last_match[:sub_type]
+            return data.each_with_object({}) { |(k, v), hsh| hsh[k] = find_and_cast_into_type(sub_type, v) }
+          end
+        else # model
+          const = {{moduleName}}.const_get(klass)
+          if const
+            if const.respond_to?(:openapi_any_of) # nested anyOf model
+              model = const.build(data)
+              return model if model
+            else
+              # raise if data contains keys that are not known to the model
+              raise unless (data.keys - const.acceptable_attributes).empty?
+              model = const.build_from_hash(data)
+              return model if model && model.valid?
+            end
+          end
+        end
+
+        raise # if no match by now, raise
+      rescue
+        raise SchemaMismatchError, "#{data} doesn't match the #{klass} type"
+      end
+    end
+  end
diff --git a/modules/openapi-generator/src/main/resources/ruby-client/partial_oneof_module.mustache b/modules/openapi-generator/src/main/resources/ruby-client/partial_oneof_module.mustache
index b2d22e222fc8..49e7b58d015e 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/partial_oneof_module.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/partial_oneof_module.mustache
@@ -123,7 +123,7 @@
               # raise if data contains keys that are not known to the model
               raise unless (data.keys - const.acceptable_attributes).empty?
               model = const.build_from_hash(data)
-              return model if model && model.valid?
+              return model if model
             end
           end
         end
diff --git a/modules/openapi-generator/src/test/resources/3_0/ruby/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/3_0/ruby/petstore-with-fake-endpoints-models-for-testing.yaml
index feb27a17b57b..0c8345a80f55 100644
--- a/modules/openapi-generator/src/test/resources/3_0/ruby/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/ruby/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -1961,6 +1961,10 @@ components:
       enum:
         - admin
         - user
+    mammal_anyof:
+      anyOf:
+        - $ref: '#/components/schemas/whale'
+        - $ref: '#/components/schemas/zebra'
     mammal_without_discriminator:
       oneOf:
         - $ref: '#/components/schemas/whale'
diff --git a/samples/client/petstore/ruby/.openapi-generator/FILES b/samples/client/petstore/ruby/.openapi-generator/FILES
index a6e825e37fcd..f12b23610fb3 100644
--- a/samples/client/petstore/ruby/.openapi-generator/FILES
+++ b/samples/client/petstore/ruby/.openapi-generator/FILES
@@ -37,6 +37,7 @@ docs/HasOnlyReadOnly.md
 docs/HealthCheckResult.md
 docs/List.md
 docs/Mammal.md
+docs/MammalAnyof.md
 docs/MammalWithoutDiscriminator.md
 docs/MapTest.md
 docs/MixedPropertiesAndAdditionalPropertiesClass.md
@@ -103,6 +104,7 @@ lib/petstore/models/has_only_read_only.rb
 lib/petstore/models/health_check_result.rb
 lib/petstore/models/list.rb
 lib/petstore/models/mammal.rb
+lib/petstore/models/mammal_anyof.rb
 lib/petstore/models/mammal_without_discriminator.rb
 lib/petstore/models/map_test.rb
 lib/petstore/models/mixed_properties_and_additional_properties_class.rb
diff --git a/samples/client/petstore/ruby/README.md b/samples/client/petstore/ruby/README.md
index 09b408b59b3d..bf91507cf8bd 100644
--- a/samples/client/petstore/ruby/README.md
+++ b/samples/client/petstore/ruby/README.md
@@ -148,6 +148,7 @@ Class | Method | HTTP request | Description
  - [Petstore::HealthCheckResult](docs/HealthCheckResult.md)
  - [Petstore::List](docs/List.md)
  - [Petstore::Mammal](docs/Mammal.md)
+ - [Petstore::MammalAnyof](docs/MammalAnyof.md)
  - [Petstore::MammalWithoutDiscriminator](docs/MammalWithoutDiscriminator.md)
  - [Petstore::MapTest](docs/MapTest.md)
  - [Petstore::MixedPropertiesAndAdditionalPropertiesClass](docs/MixedPropertiesAndAdditionalPropertiesClass.md)
diff --git a/samples/client/petstore/ruby/docs/MammalAnyof.md b/samples/client/petstore/ruby/docs/MammalAnyof.md
new file mode 100644
index 000000000000..bd21a482f1a6
--- /dev/null
+++ b/samples/client/petstore/ruby/docs/MammalAnyof.md
@@ -0,0 +1,24 @@
+# Petstore::MammalAnyof
+
+## Properties
+
+| Name | Type | Description | Notes |
+| ---- | ---- | ----------- | ----- |
+| **has_baleen** | **Boolean** |  | [optional] |
+| **has_teeth** | **Boolean** |  | [optional] |
+| **classname** | **String** |  |  |
+| **type** | **String** |  | [optional] |
+
+## Example
+
+```ruby
+require 'petstore'
+
+instance = Petstore::MammalAnyof.new(
+  has_baleen: null,
+  has_teeth: null,
+  classname: null,
+  type: null
+)
+```
+
diff --git a/samples/client/petstore/ruby/lib/petstore.rb b/samples/client/petstore/ruby/lib/petstore.rb
index 08fdc5bf2bc2..455edf770585 100644
--- a/samples/client/petstore/ruby/lib/petstore.rb
+++ b/samples/client/petstore/ruby/lib/petstore.rb
@@ -42,6 +42,7 @@
 require 'petstore/models/health_check_result'
 require 'petstore/models/list'
 require 'petstore/models/mammal'
+require 'petstore/models/mammal_anyof'
 require 'petstore/models/mammal_without_discriminator'
 require 'petstore/models/map_test'
 require 'petstore/models/mixed_properties_and_additional_properties_class'
diff --git a/samples/client/petstore/ruby/lib/petstore/models/mammal_anyof.rb b/samples/client/petstore/ruby/lib/petstore/models/mammal_anyof.rb
new file mode 100644
index 000000000000..554b05586174
--- /dev/null
+++ b/samples/client/petstore/ruby/lib/petstore/models/mammal_anyof.rb
@@ -0,0 +1,104 @@
+=begin
+#OpenAPI Petstore
+
+#This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 7.0.0-SNAPSHOT
+
+=end
+
+require 'date'
+require 'time'
+
+module Petstore
+  module MammalAnyof
+    class << self
+      # List of class defined in anyOf (OpenAPI v3)
+      def openapi_any_of
+        [
+          :'Whale',
+          :'Zebra'
+        ]
+      end
+
+      # Builds the object
+      # @param [Mixed] Data to be matched against the list of anyOf items
+      # @return [Object] Returns the model or the data itself
+      def build(data)
+        # Go through the list of anyOf items and attempt to identify the appropriate one.
+        # Note:
+        # - No advanced validation of types in some cases (e.g. "x: { type: string }" will happily match { x: 123 })
+        #   due to the way the deserialization is made in the base_object template (it just casts without verifying).
+        # - TODO: scalar values are de facto behaving as if they were nullable.
+        # - TODO: logging when debugging is set.
+        openapi_any_of.each do |klass|
+          begin
+            next if klass == :AnyType # "nullable: true"
+            typed_data = find_and_cast_into_type(klass, data)
+            return typed_data if typed_data
+          rescue # rescue all errors so we keep iterating even if the current item lookup raises
+          end
+        end
+
+        openapi_any_of.include?(:AnyType) ? data : nil
+      end
+
+      private
+
+      SchemaMismatchError = Class.new(StandardError)
+
+      # Note: 'File' is missing here because in the regular case we get the data _after_ a call to JSON.parse.
+      def find_and_cast_into_type(klass, data)
+        return if data.nil?
+
+        case klass.to_s
+        when 'Boolean'
+          return data if data.instance_of?(TrueClass) || data.instance_of?(FalseClass)
+        when 'Float'
+          return data if data.instance_of?(Float)
+        when 'Integer'
+          return data if data.instance_of?(Integer)
+        when 'Time'
+          return Time.parse(data)
+        when 'Date'
+          return Date.parse(data)
+        when 'String'
+          return data if data.instance_of?(String)
+        when 'Object' # "type: object"
+          return data if data.instance_of?(Hash)
+        when /\AArray<(?<sub_type>.+)>\z/ # "type: array"
+          if data.instance_of?(Array)
+            sub_type = Regexp.last_match[:sub_type]
+            return data.map { |item| find_and_cast_into_type(sub_type, item) }
+          end
+        when /\AHash<String, (?<sub_type>.+)>\z/ # "type: object" with "additionalProperties: { ... }"
+          if data.instance_of?(Hash) && data.keys.all? { |k| k.instance_of?(Symbol) || k.instance_of?(String) }
+            sub_type = Regexp.last_match[:sub_type]
+            return data.each_with_object({}) { |(k, v), hsh| hsh[k] = find_and_cast_into_type(sub_type, v) }
+          end
+        else # model
+          const = Petstore.const_get(klass)
+          if const
+            if const.respond_to?(:openapi_any_of) # nested anyOf model
+              model = const.build(data)
+              return model if model
+            else
+              # raise if data contains keys that are not known to the model
+              raise unless (data.keys - const.acceptable_attributes).empty?
+              model = const.build_from_hash(data)
+              return model if model && model.valid?
+            end
+          end
+        end
+
+        raise # if no match by now, raise
+      rescue
+        raise SchemaMismatchError, "#{data} doesn't match the #{klass} type"
+      end
+    end
+  end
+
+end
diff --git a/samples/client/petstore/ruby/lib/petstore/models/mammal_without_discriminator.rb b/samples/client/petstore/ruby/lib/petstore/models/mammal_without_discriminator.rb
index 601f0d01d4d7..d9136c15f666 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/mammal_without_discriminator.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/mammal_without_discriminator.rb
@@ -90,7 +90,7 @@ def find_and_cast_into_type(klass, data)
               # raise if data contains keys that are not known to the model
               raise unless (data.keys - const.acceptable_attributes).empty?
               model = const.build_from_hash(data)
-              return model if model && model.valid?
+              return model if model
             end
           end
         end
diff --git a/samples/client/petstore/ruby/lib/petstore/models/whale.rb b/samples/client/petstore/ruby/lib/petstore/models/whale.rb
index 69f96d32d2f0..bdb9ee2bd2ac 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/whale.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/whale.rb
@@ -75,12 +75,15 @@ def initialize(attributes = {})
 
       if attributes.key?(:'classname')
         self.classname = attributes[:'classname']
+      else
+        self.classname = nil
       end
     end
 
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @classname.nil?
         invalid_properties.push('invalid value for "classname", classname cannot be nil.')
@@ -92,6 +95,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       return false if @classname.nil?
       true
     end
@@ -122,37 +126,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/lib/petstore/models/zebra.rb b/samples/client/petstore/ruby/lib/petstore/models/zebra.rb
index df3904e31ff8..2e8b19214875 100644
--- a/samples/client/petstore/ruby/lib/petstore/models/zebra.rb
+++ b/samples/client/petstore/ruby/lib/petstore/models/zebra.rb
@@ -89,12 +89,15 @@ def initialize(attributes = {})
 
       if attributes.key?(:'classname')
         self.classname = attributes[:'classname']
+      else
+        self.classname = nil
       end
     end
 
     # Show invalid properties with the reasons. Usually used together with valid?
     # @return Array for valid properties with the reasons
     def list_invalid_properties
+      warn '[DEPRECATED] the `list_invalid_properties` method is obsolete'
       invalid_properties = Array.new
       if @classname.nil?
         invalid_properties.push('invalid value for "classname", classname cannot be nil.')
@@ -106,6 +109,7 @@ def list_invalid_properties
     # Check to see if the all the properties in the model are valid
     # @return true if the model is valid
     def valid?
+      warn '[DEPRECATED] the `valid?` method is obsolete'
       type_validator = EnumAttributeValidator.new('String', ["plains", "mountain", "grevys"])
       return false unless type_validator.valid?(@type)
       return false if @classname.nil?
@@ -147,37 +151,30 @@ def hash
     # @param [Hash] attributes Model attributes in the form of hash
     # @return [Object] Returns the model itself
     def self.build_from_hash(attributes)
-      new.build_from_hash(attributes)
-    end
-
-    # Builds the object from hash
-    # @param [Hash] attributes Model attributes in the form of hash
-    # @return [Object] Returns the model itself
-    def build_from_hash(attributes)
       return nil unless attributes.is_a?(Hash)
       attributes = attributes.transform_keys(&:to_sym)
-      self.class.openapi_types.each_pair do |key, type|
-        if attributes[self.class.attribute_map[key]].nil? && self.class.openapi_nullable.include?(key)
-          self.send("#{key}=", nil)
+      transformed_hash = {}
+      openapi_types.each_pair do |key, type|
+        if attributes.key?(attribute_map[key]) && attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = nil
         elsif type =~ /\AArray<(.*)>/i
           # check to ensure the input is an array given that the attribute
           # is documented as an array but the input is not
-          if attributes[self.class.attribute_map[key]].is_a?(Array)
-            self.send("#{key}=", attributes[self.class.attribute_map[key]].map { |v| _deserialize($1, v) })
+          if attributes[attribute_map[key]].is_a?(Array)
+            transformed_hash["#{key}"] = attributes[attribute_map[key]].map { |v| _deserialize($1, v) }
           end
-        elsif !attributes[self.class.attribute_map[key]].nil?
-          self.send("#{key}=", _deserialize(type, attributes[self.class.attribute_map[key]]))
+        elsif !attributes[attribute_map[key]].nil?
+          transformed_hash["#{key}"] = _deserialize(type, attributes[attribute_map[key]])
         end
       end
-
-      self
+      new(transformed_hash)
     end
 
     # Deserializes the data based on type
     # @param string type Data type
     # @param string value Value to be deserialized
     # @return [Object] Deserialized data
-    def _deserialize(type, value)
+    def self._deserialize(type, value)
       case type.to_sym
       when :Time
         Time.parse(value)
diff --git a/samples/client/petstore/ruby/spec/custom/model_spec.rb b/samples/client/petstore/ruby/spec/custom/model_spec.rb
index 8eac76dbe19a..8e7af2c0db3e 100644
--- a/samples/client/petstore/ruby/spec/custom/model_spec.rb
+++ b/samples/client/petstore/ruby/spec/custom/model_spec.rb
@@ -9,6 +9,27 @@
   after do
   end
 
+  describe "anyOf" do
+    it "should construct a new anyOf object mammal_anyof" do
+      whale = Petstore::Whale.new('classname' => "Whale", 'has_teeth' => true)
+      zebra = Petstore::Zebra.new('classname' => "Zebra", 'type' => 'plains')
+
+      # oneOf whale test
+      expect(whale.to_hash[:'classname']).to eq("Whale")
+      result = Petstore::MammalAnyof.build(whale.to_hash)
+      expect(result).to be_a Petstore::Whale
+
+      # oneOf zebra test
+      expect(zebra.to_hash[:'classname']).to eq("Zebra")
+      result2 = Petstore::MammalAnyof.build(zebra.to_hash)
+      expect(result2).to be_a Petstore::Zebra
+
+      # invalid data/hash should result in nil
+      result3 = Petstore::MammalAnyof.build({"something": 123})
+      expect(result3).to be_nil
+    end
+  end
+
   describe "oneOf" do
     it "should construct a new oneOf object mammal" do
       whale = Petstore::Whale.new('classname' => "Whale", 'has_teeth' => true)
diff --git a/samples/client/petstore/ruby/spec/models/mammal_anyof_spec.rb b/samples/client/petstore/ruby/spec/models/mammal_anyof_spec.rb
new file mode 100644
index 000000000000..878c48c246ae
--- /dev/null
+++ b/samples/client/petstore/ruby/spec/models/mammal_anyof_spec.rb
@@ -0,0 +1,21 @@
+=begin
+#OpenAPI Petstore
+
+#This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+
+The version of the OpenAPI document: 1.0.0
+
+Generated by: https://openapi-generator.tech
+OpenAPI Generator version: 7.0.0-SNAPSHOT
+
+=end
+
+require 'spec_helper'
+require 'json'
+require 'date'
+
+# Unit tests for Petstore::MammalAnyof
+# Automatically generated by openapi-generator (https://openapi-generator.tech)
+# Please update as you see appropriate
+describe Petstore::MammalAnyof do
+end