diff --git a/activemodel/lib/active_model/validations/numericality.rb b/activemodel/lib/active_model/validations/numericality.rb
index c7871c4ed8..166b29df47 100644
--- a/activemodel/lib/active_model/validations/numericality.rb
+++ b/activemodel/lib/active_model/validations/numericality.rb
@@ -11,7 +11,7 @@ module ActiveModel
       RANGE_CHECKS = { in: :in? }
       NUMBER_CHECKS = { odd: :odd?, even: :even? }
 
-      RESERVED_OPTIONS = COMPARE_CHECKS.keys + NUMBER_CHECKS.keys + RANGE_CHECKS.keys + [:only_integer]
+      RESERVED_OPTIONS = COMPARE_CHECKS.keys + NUMBER_CHECKS.keys + RANGE_CHECKS.keys + [:only_integer, :only_numeric]
 
       INTEGER_REGEX = /\A[+-]?\d+\z/
 
@@ -90,6 +90,10 @@ module ActiveModel
       end
 
       def is_number?(raw_value, precision, scale)
+        if options[:only_numeric] && !raw_value.is_a?(Numeric)
+          return false
+        end
+
         !parse_as_number(raw_value, precision, scale).nil?
       rescue ArgumentError, TypeError
         false
@@ -162,6 +166,9 @@ module ActiveModel
       # * <tt>:message</tt> - A custom error message (default is: "is not a number").
       # * <tt>:only_integer</tt> - Specifies whether the value has to be an
       #   integer (default is +false+).
+      # * <tt>:only_numeric</tt> - Specifies whether the value has to be an
+      #   instance of Numeric (default is +false+). The default behavior is to
+      #   attempt parsing the value if it is a String.
       # * <tt>:allow_nil</tt> - Skip validation if attribute is +nil+ (default is
       #   +false+). Notice that for Integer and Float columns empty strings are
       #   converted to +nil+.
diff --git a/activemodel/test/cases/validations/numericality_validation_test.rb b/activemodel/test/cases/validations/numericality_validation_test.rb
index 8fd6e706b0..37c34d6543 100644
--- a/activemodel/test/cases/validations/numericality_validation_test.rb
+++ b/activemodel/test/cases/validations/numericality_validation_test.rb
@@ -19,8 +19,10 @@ class NumericalityValidationTest < ActiveModel::TestCase
   BIGDECIMAL_STRINGS = %w(12345678901234567890.1234567890) # 30 significant digits
   FLOAT_STRINGS = %w(0.0 +0.0 -0.0 10.0 10.5 -10.5 -0.0001 -090.1 90.1e1 -90.1e5 -90.1e-5 90e-5)
   INTEGER_STRINGS = %w(0 +0 -0 10 +10 -10 0090 -090)
-  FLOATS = [0.0, 10.0, 10.5, -10.5, -0.0001] + FLOAT_STRINGS
-  INTEGERS = [0, 10, -10] + INTEGER_STRINGS
+  NUMERIC_FLOATS = [0.0, 10.0, 10.5, -10.5, -0.0001]
+  NUMERIC_INTEGERS = [0, 10, -10]
+  FLOATS = NUMERIC_FLOATS + FLOAT_STRINGS
+  INTEGERS = NUMERIC_INTEGERS + INTEGER_STRINGS
   BIGDECIMAL = BIGDECIMAL_STRINGS.collect! { |bd| BigDecimal(bd) }
   JUNK = ["not a number", "42 not a number", "0xdeadbeef", "-0xdeadbeef", "+0xdeadbeef", "0xinvalidhex", "0Xdeadbeef", "00-1", "--3", "+-3", "+3-1", "-+019.0", "12.12.13.12", "123\nnot a number"]
   INFINITY = [1.0 / 0.0]
@@ -74,6 +76,20 @@ class NumericalityValidationTest < ActiveModel::TestCase
     assert_valid_values(FLOATS + INTEGERS + BIGDECIMAL + INFINITY)
   end
 
+  def test_validates_numericality_of_with_numeric_only
+    Topic.validates_numericality_of :approved, only_numeric: true
+
+    assert_invalid_values(NIL + BLANK + JUNK + FLOAT_STRINGS + INTEGER_STRINGS)
+    assert_valid_values(NUMERIC_FLOATS + NUMERIC_INTEGERS + BIGDECIMAL + INFINITY)
+  end
+
+  def test_validates_numericality_of_with_numeric_only_and_nil_allowed
+    Topic.validates_numericality_of :approved, only_numeric: true, allow_nil: true
+
+    assert_invalid_values(JUNK + BLANK + FLOAT_STRINGS + INTEGER_STRINGS)
+    assert_valid_values(NIL + NUMERIC_FLOATS + NUMERIC_INTEGERS + BIGDECIMAL + INFINITY)
+  end
+
   def test_validates_numericality_with_greater_than
     Topic.validates_numericality_of :approved, greater_than: 10