diff --git a/lib/json.rb b/lib/json.rb
index 8b1673d5..c28e853e 100644
--- a/lib/json.rb
+++ b/lib/json.rb
@@ -378,13 +378,13 @@
 #   json1 = JSON.generate(ruby)
 #   ruby1 = JSON.parse(json1, create_additions: true)
 #   # Make a nice display.
-#   display = <<EOT
-#   Generated JSON:
-#     Without addition:  #{json0} (#{json0.class})
-#     With addition:     #{json1} (#{json1.class})
-#   Parsed JSON:
-#     Without addition:  #{ruby0.inspect} (#{ruby0.class})
-#     With addition:     #{ruby1.inspect} (#{ruby1.class})
+#   display = <<~EOT
+#     Generated JSON:
+#       Without addition:  #{json0} (#{json0.class})
+#       With addition:     #{json1} (#{json1.class})
+#     Parsed JSON:
+#       Without addition:  #{ruby0.inspect} (#{ruby0.class})
+#       With addition:     #{ruby1.inspect} (#{ruby1.class})
 #   EOT
 #   puts display
 #
@@ -562,13 +562,13 @@
 #   json1 = JSON.generate(foo1)
 #   obj1 = JSON.parse(json1, create_additions: true)
 #   #   Make a nice display.
-#   display = <<EOT
-#   Generated JSON:
-#     Without custom addition:  #{json0} (#{json0.class})
-#     With custom addition:     #{json1} (#{json1.class})
-#   Parsed JSON:
-#     Without custom addition:  #{obj0.inspect} (#{obj0.class})
-#     With custom addition:     #{obj1.inspect} (#{obj1.class})
+#   display = <<~EOT
+#     Generated JSON:
+#       Without custom addition:  #{json0} (#{json0.class})
+#       With custom addition:     #{json1} (#{json1.class})
+#     Parsed JSON:
+#       Without custom addition:  #{obj0.inspect} (#{obj0.class})
+#       With custom addition:     #{obj1.inspect} (#{obj1.class})
 #   EOT
 #   puts display
 #
diff --git a/lib/json/common.rb b/lib/json/common.rb
index bb37820a..182bb1c0 100644
--- a/lib/json/common.rb
+++ b/lib/json/common.rb
@@ -195,17 +195,17 @@ class MissingUnicodeSupport < JSONError; end
   # {Parsing \JSON}[#module-JSON-label-Parsing+JSON].
   #
   # Parses nested JSON objects:
-  #   source = <<-EOT
-  #   {
-  #   "name": "Dave",
-  #     "age" :40,
-  #     "hats": [
-  #       "Cattleman's",
-  #       "Panama",
-  #       "Tophat"
-  #     ]
-  #   }
-  #   EOT
+  #   source = <<~JSON
+  #     {
+  #     "name": "Dave",
+  #       "age" :40,
+  #       "hats": [
+  #         "Cattleman's",
+  #         "Panama",
+  #         "Tophat"
+  #       ]
+  #     }
+  #   JSON
   #   ruby = JSON.parse(source)
   #   ruby # => {"name"=>"Dave", "age"=>40, "hats"=>["Cattleman's", "Panama", "Tophat"]}
   #
@@ -445,17 +445,17 @@ class << self
   # <tt>parse(source, opts)</tt>;  see #parse.
   #
   # Source for following examples:
-  #   source = <<-EOT
-  #   {
-  #   "name": "Dave",
-  #     "age" :40,
-  #     "hats": [
-  #       "Cattleman's",
-  #       "Panama",
-  #       "Tophat"
-  #     ]
-  #   }
-  #   EOT
+  #   source = <<~JSON
+  #     {
+  #       "name": "Dave",
+  #       "age" :40,
+  #       "hats": [
+  #         "Cattleman's",
+  #         "Panama",
+  #         "Tophat"
+  #       ]
+  #     }
+  #   JSON
   #
   # Load a \String:
   #   ruby = JSON.load(source)
diff --git a/test/json/json_generator_test.rb b/test/json/json_generator_test.rb
index 32712c83..01e412c9 100755
--- a/test/json/json_generator_test.rb
+++ b/test/json/json_generator_test.rb
@@ -19,24 +19,24 @@ def setup
     }
     @json2 = '{"a":2,"b":3.141,"c":"c","d":[1,"b",3.14],"e":{"foo":"bar"},' +
       '"g":"\\"\\u0000\\u001f","h":1000.0,"i":0.001}'
-    @json3 = <<'EOT'.chomp
-{
-  "a": 2,
-  "b": 3.141,
-  "c": "c",
-  "d": [
-    1,
-    "b",
-    3.14
-  ],
-  "e": {
-    "foo": "bar"
-  },
-  "g": "\"\u0000\u001f",
-  "h": 1000.0,
-  "i": 0.001
-}
-EOT
+    @json3 = <<~'JSON'.chomp
+      {
+        "a": 2,
+        "b": 3.141,
+        "c": "c",
+        "d": [
+          1,
+          "b",
+          3.14
+        ],
+        "e": {
+          "foo": "bar"
+        },
+        "g": "\"\u0000\u001f",
+        "h": 1000.0,
+        "i": 0.001
+      }
+    JSON
   end
 
   def silence
@@ -93,13 +93,13 @@ def test_generate_pretty
     assert_equal('{}', json)
 
     json = pretty_generate({1=>{}, 2=>[], 3=>4})
-    assert_equal(<<'EOT'.chomp, json)
-{
-  "1": {},
-  "2": [],
-  "3": 4
-}
-EOT
+    assert_equal(<<~'JSON'.chomp, json)
+      {
+        "1": {},
+        "2": [],
+        "3": 4
+      }
+    JSON
 
     json = pretty_generate(@hash)
     # hashes aren't (insertion) ordered on every ruby implementation
@@ -108,11 +108,11 @@ def test_generate_pretty
     parsed_json = parse(json)
     assert_equal(@hash, parsed_json)
     json = pretty_generate({1=>2})
-    assert_equal(<<'EOT'.chomp, json)
-{
-  "1": 2
-}
-EOT
+    assert_equal(<<~'JSON'.chomp, json)
+      {
+        "1": 2
+      }
+    JSON
     parsed_json = parse(json)
     assert_equal({"1"=>2}, parsed_json)
     assert_equal '666', pretty_generate(666)
@@ -121,14 +121,14 @@ def test_generate_pretty
   def test_generate_custom
     state = State.new(:space_before => " ", :space => "   ", :indent => "<i>", :object_nl => "\n", :array_nl => "<a_nl>")
     json = generate({1=>{2=>3,4=>[5,6]}}, state)
-    assert_equal(<<'EOT'.chomp, json)
-{
-<i>"1" :   {
-<i><i>"2" :   3,
-<i><i>"4" :   [<a_nl><i><i><i>5,<a_nl><i><i><i>6<a_nl><i><i>]
-<i>}
-}
-EOT
+    assert_equal(<<~'JSON'.chomp, json)
+      {
+      <i>"1" :   {
+      <i><i>"2" :   3,
+      <i><i>"4" :   [<a_nl><i><i><i>5,<a_nl><i><i><i>6<a_nl><i><i>]
+      <i>}
+      }
+    JSON
   end
 
   def test_fast_generate
diff --git a/test/json/json_parser_test.rb b/test/json/json_parser_test.rb
index 8d3c0c17..ffc67ef6 100644
--- a/test/json/json_parser_test.rb
+++ b/test/json/json_parser_test.rb
@@ -247,50 +247,50 @@ def test_freeze
   end
 
   def test_parse_comments
-    json = <<EOT
-{
-  "key1":"value1", // eol comment
-  "key2":"value2"  /* multi line
-                    *  comment */,
-  "key3":"value3"  /* multi line
-                    // nested eol comment
-                    *  comment */
-}
-EOT
+    json = <<~JSON
+      {
+        "key1":"value1", // eol comment
+        "key2":"value2"  /* multi line
+                          *  comment */,
+        "key3":"value3"  /* multi line
+                          // nested eol comment
+                          *  comment */
+      }
+    JSON
     assert_equal(
       { "key1" => "value1", "key2" => "value2", "key3" => "value3" },
       parse(json))
-    json = <<EOT
-{
-  "key1":"value1"  /* multi line
-                    // nested eol comment
-                    /* illegal nested multi line comment */
-                    *  comment */
-}
-EOT
+    json = <<~JSON
+      {
+        "key1":"value1"  /* multi line
+                          // nested eol comment
+                          /* illegal nested multi line comment */
+                          *  comment */
+      }
+    JSON
     assert_raise(ParserError) { parse(json) }
-    json = <<EOT
-{
-  "key1":"value1"  /* multi line
-                    // nested eol comment
-                    /* legal nested multi line comment start sequence */
-}
-EOT
+    json = <<~JSON
+      {
+        "key1":"value1"  /* multi line
+                          // nested eol comment
+                          /* legal nested multi line comment start sequence */
+      }
+    JSON
     assert_equal({ "key1" => "value1" }, parse(json))
-    json = <<EOT
-{
-  "key1":"value1"  /* multi line
-                   // nested eol comment
-                   closed multi comment */
-                   and again, throw an Error */
-}
-EOT
+    json = <<~JSON
+      {
+        "key1":"value1"  /* multi line
+                         // nested eol comment
+                         closed multi comment */
+                         and again, throw an Error */
+      }
+    JSON
     assert_raise(ParserError) { parse(json) }
-    json = <<EOT
-{
-  "key1":"value1"  /*/*/
-}
-EOT
+    json = <<~JSON
+      {
+        "key1":"value1"  /*/*/
+      }
+    JSON
     assert_equal({ "key1" => "value1" }, parse(json))
   end