diff --git a/lib/grape.rb b/lib/grape.rb
index 963e37364..d0a6b8efc 100644
--- a/lib/grape.rb
+++ b/lib/grape.rb
@@ -22,8 +22,8 @@
 require 'active_support/core_ext/object/duplicable'
 require 'active_support/core_ext/string/output_safety'
 require 'active_support/core_ext/string/exclude'
+require 'active_support/core_ext/string/inflections'
 require 'active_support/deprecation'
-require 'active_support/inflector'
 require 'active_support/ordered_options'
 require 'active_support/notifications'
 
diff --git a/lib/grape/validations.rb b/lib/grape/validations.rb
index 9ae22ae6a..5df7b2f3b 100644
--- a/lib/grape/validations.rb
+++ b/lib/grape/validations.rb
@@ -4,27 +4,19 @@ module Grape
   module Validations
     module_function
 
-    def validators
-      @validators ||= {}
-    end
-
-    # Register a new validator, so it can be used to validate parameters.
-    # @param short_name [String] all lower-case, no spaces
-    # @param klass [Class] the validator class. Should inherit from
-    #   Grape::Validations::Validators::Base.
-    def register_validator(short_name, klass)
-      validators[short_name] = klass
-    end
-
-    def deregister_validator(short_name)
-      validators.delete(short_name)
-    end
-
     def require_validator(short_name)
-      str_name = short_name.to_s
-      validators.fetch(str_name) { Grape::Validations::Validators.const_get(:"#{str_name.camelize}Validator") }
+      ValidatorsRegistry[short_name]
     rescue NameError
       raise Grape::Exceptions::UnknownValidator, short_name
     end
+
+    class ValidatorsRegistry < Grape::Util::Cache
+      def initialize
+        super
+        @cache = Hash.new do |h, name|
+          h[name] = Grape::Validations::Validators.const_get(:"#{name.to_s.camelize}Validator")
+        end
+      end
+    end
   end
 end
diff --git a/lib/grape/validations/validators/base.rb b/lib/grape/validations/validators/base.rb
index 3dd49fd79..eeb0bcfc1 100644
--- a/lib/grape/validations/validators/base.rb
+++ b/lib/grape/validations/validators/base.rb
@@ -58,14 +58,6 @@ def validate!(params)
           raise Grape::Exceptions::ValidationArrayErrors.new(array_errors) if array_errors.any?
         end
 
-        def self.inherited(klass)
-          super
-          return if klass.name.blank?
-
-          short_validator_name = klass.name.demodulize.underscore.delete_suffix('_validator')
-          Validations.register_validator(short_validator_name, klass)
-        end
-
         def message(default_key = nil)
           options = instance_variable_get(:@option)
           options_key?(:message) ? options[:message] : default_key
diff --git a/spec/grape/validations_spec.rb b/spec/grape/validations_spec.rb
index 19dd130f0..123a1a8e3 100644
--- a/spec/grape/validations_spec.rb
+++ b/spec/grape/validations_spec.rb
@@ -2026,5 +2026,20 @@ def validate_param!(attr_name, params)
         expect { subject }.to raise_error(Grape::Exceptions::UnknownValidator)
       end
     end
+
+    context 'when custom' do
+      let(:short_name) { :custom }
+      let(:custom_validator) do
+        Class.new(Grape::Validations::Validators::Base) do
+          def validate_param!(_attr_name, _params); end
+        end
+      end
+
+      before do
+        stub_const('Grape::Validations::Validators::CustomValidator', custom_validator)
+      end
+
+      it { is_expected.to be(Grape::Validations::Validators::CustomValidator) }
+    end
   end
 end