diff --git a/src/linter/CMakeLists.txt b/src/linter/CMakeLists.txt
index 49b36ee..2d37c86 100644
--- a/src/linter/CMakeLists.txt
+++ b/src/linter/CMakeLists.txt
@@ -29,6 +29,7 @@ noa_library(NAMESPACE sourcemeta PROJECT alterschema NAME linter
     redundant/else_without_if.h
     redundant/empty_dependencies.h
     redundant/empty_dependent_required.h
+    redundant/if_without_then_else.h
     redundant/items_array_default.h
     redundant/items_schema_default.h
     redundant/max_contains_without_contains.h
diff --git a/src/linter/linter.cc b/src/linter/linter.cc
index 7ce22f9..1dc9dfb 100644
--- a/src/linter/linter.cc
+++ b/src/linter/linter.cc
@@ -39,6 +39,7 @@ auto contains_any(const T &container, const T &values) -> bool {
 #include "redundant/else_without_if.h"
 #include "redundant/empty_dependencies.h"
 #include "redundant/empty_dependent_required.h"
+#include "redundant/if_without_then_else.h"
 #include "redundant/items_array_default.h"
 #include "redundant/items_schema_default.h"
 #include "redundant/max_contains_without_contains.h"
@@ -82,6 +83,7 @@ auto add(Bundle &bundle, const LinterCategory category) -> void {
       bundle.add<ElseWithoutIf>();
       bundle.add<EmptyDependencies>();
       bundle.add<EmptyDependentRequired>();
+      bundle.add<IfWithoutThenElse>();
       bundle.add<ItemsArrayDefault>();
       bundle.add<ItemsSchemaDefault>();
       bundle.add<MaxContainsWithoutContains>();
diff --git a/src/linter/redundant/if_without_then_else.h b/src/linter/redundant/if_without_then_else.h
new file mode 100644
index 0000000..5a9735a
--- /dev/null
+++ b/src/linter/redundant/if_without_then_else.h
@@ -0,0 +1,24 @@
+class IfWithoutThenElse final : public Rule {
+public:
+  IfWithoutThenElse()
+      : Rule{"if_without_then_else",
+             "The `if` keyword is meaningless "
+             "without the presence of the `then` or `else` keywords"} {};
+
+  [[nodiscard]] auto
+  condition(const sourcemeta::jsontoolkit::JSON &schema, const std::string &,
+            const std::set<std::string> &vocabularies,
+            const sourcemeta::jsontoolkit::Pointer &) const -> bool override {
+    return contains_any(
+               vocabularies,
+               {"https://json-schema.org/draft/2020-12/vocab/applicator",
+                "https://json-schema.org/draft/2019-09/vocab/applicator",
+                "http://json-schema.org/draft-07/schema#"}) &&
+           schema.is_object() && schema.defines("if") &&
+           !schema.defines("then") && !schema.defines("else");
+  }
+
+  auto transform(Transformer &transformer) const -> void override {
+    transformer.erase("if");
+  }
+};
diff --git a/test/linter/2019_09_test.cc b/test/linter/2019_09_test.cc
index 939b004..59023e8 100644
--- a/test/linter/2019_09_test.cc
+++ b/test/linter/2019_09_test.cc
@@ -262,6 +262,23 @@ TEST(Lint_2019_09, else_without_if_2) {
   EXPECT_EQ(document, expected);
 }
 
+TEST(Lint_2019_09, if_without_then_else_1) {
+  sourcemeta::jsontoolkit::JSON document =
+      sourcemeta::jsontoolkit::parse(R"JSON({
+    "$schema": "https://json-schema.org/draft/2019-09/schema",
+    "if": true
+  })JSON");
+
+  LINT_AND_FIX(document);
+
+  const sourcemeta::jsontoolkit::JSON expected =
+      sourcemeta::jsontoolkit::parse(R"JSON({
+    "$schema": "https://json-schema.org/draft/2019-09/schema"
+  })JSON");
+
+  EXPECT_EQ(document, expected);
+}
+
 TEST(Lint_2019_09, unevaluated_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
@@ -824,7 +841,7 @@ TEST(Lint_2019_09, dependent_required_tautology_2) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_2019_09, properties_default) {
+TEST(Lint_2019_09, properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema",
@@ -841,7 +858,7 @@ TEST(Lint_2019_09, properties_default) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_2019_09, pattern_properties_default) {
+TEST(Lint_2019_09, pattern_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "https://json-schema.org/draft/2019-09/schema",
diff --git a/test/linter/2020_12_test.cc b/test/linter/2020_12_test.cc
index e19707d..3a54d5d 100644
--- a/test/linter/2020_12_test.cc
+++ b/test/linter/2020_12_test.cc
@@ -262,6 +262,23 @@ TEST(Lint_2020_12, else_without_if_2) {
   EXPECT_EQ(document, expected);
 }
 
+TEST(Lint_2020_12, if_without_then_else_1) {
+  sourcemeta::jsontoolkit::JSON document =
+      sourcemeta::jsontoolkit::parse(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema",
+    "if": true
+  })JSON");
+
+  LINT_AND_FIX(document);
+
+  const sourcemeta::jsontoolkit::JSON expected =
+      sourcemeta::jsontoolkit::parse(R"JSON({
+    "$schema": "https://json-schema.org/draft/2020-12/schema"
+  })JSON");
+
+  EXPECT_EQ(document, expected);
+}
+
 TEST(Lint_2020_12, unevaluated_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
@@ -807,7 +824,7 @@ TEST(Lint_2020_12, dependent_required_tautology_2) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_2020_12, properties_default) {
+TEST(Lint_2020_12, properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
@@ -824,7 +841,7 @@ TEST(Lint_2020_12, properties_default) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_2020_12, pattern_properties_default) {
+TEST(Lint_2020_12, pattern_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "https://json-schema.org/draft/2020-12/schema",
diff --git a/test/linter/draft1_test.cc b/test/linter/draft1_test.cc
index af4eadf..f998732 100644
--- a/test/linter/draft1_test.cc
+++ b/test/linter/draft1_test.cc
@@ -220,7 +220,7 @@ TEST(Lint_draft1, minimum_real_for_integer_1) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft1, properties_default) {
+TEST(Lint_draft1, properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-01/schema#",
diff --git a/test/linter/draft2_test.cc b/test/linter/draft2_test.cc
index 7aaf3d1..bcd989d 100644
--- a/test/linter/draft2_test.cc
+++ b/test/linter/draft2_test.cc
@@ -220,7 +220,7 @@ TEST(Lint_draft2, minimum_real_for_integer_1) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft2, properties_default) {
+TEST(Lint_draft2, properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-02/schema#",
diff --git a/test/linter/draft3_test.cc b/test/linter/draft3_test.cc
index 3f85ab7..5f6676d 100644
--- a/test/linter/draft3_test.cc
+++ b/test/linter/draft3_test.cc
@@ -269,7 +269,7 @@ TEST(Lint_draft3, dependent_required_tautology_2) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft3, properties_default) {
+TEST(Lint_draft3, properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-03/schema#",
@@ -286,7 +286,7 @@ TEST(Lint_draft3, properties_default) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft3, pattern_properties_default) {
+TEST(Lint_draft3, pattern_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-03/schema#",
diff --git a/test/linter/draft4_test.cc b/test/linter/draft4_test.cc
index 6eebdd8..f2bcde5 100644
--- a/test/linter/draft4_test.cc
+++ b/test/linter/draft4_test.cc
@@ -323,7 +323,7 @@ TEST(Lint_draft4, dependent_required_tautology_2) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft4, properties_default) {
+TEST(Lint_draft4, properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-04/schema#",
@@ -340,7 +340,7 @@ TEST(Lint_draft4, properties_default) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft4, pattern_properties_default) {
+TEST(Lint_draft4, pattern_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-04/schema#",
diff --git a/test/linter/draft6_test.cc b/test/linter/draft6_test.cc
index 4456855..acfdbc2 100644
--- a/test/linter/draft6_test.cc
+++ b/test/linter/draft6_test.cc
@@ -474,7 +474,7 @@ TEST(Lint_draft6, dependent_required_tautology_2) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft6, properties_default) {
+TEST(Lint_draft6, properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-06/schema#",
@@ -491,7 +491,7 @@ TEST(Lint_draft6, properties_default) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft6, pattern_properties_default) {
+TEST(Lint_draft6, pattern_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-06/schema#",
diff --git a/test/linter/draft7_test.cc b/test/linter/draft7_test.cc
index 88d766f..b6b4a3f 100644
--- a/test/linter/draft7_test.cc
+++ b/test/linter/draft7_test.cc
@@ -169,6 +169,23 @@ TEST(Lint_draft7, else_without_if_2) {
   EXPECT_EQ(document, expected);
 }
 
+TEST(Lint_draft7, if_without_then_else_1) {
+  sourcemeta::jsontoolkit::JSON document =
+      sourcemeta::jsontoolkit::parse(R"JSON({
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "if": true
+  })JSON");
+
+  LINT_AND_FIX(document);
+
+  const sourcemeta::jsontoolkit::JSON expected =
+      sourcemeta::jsontoolkit::parse(R"JSON({
+    "$schema": "http://json-schema.org/draft-07/schema#"
+  })JSON");
+
+  EXPECT_EQ(document, expected);
+}
+
 TEST(Lint_draft7, additional_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
@@ -565,7 +582,7 @@ TEST(Lint_draft7, dependent_required_tautology_2) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft7, properties_default) {
+TEST(Lint_draft7, properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-07/schema#",
@@ -582,7 +599,7 @@ TEST(Lint_draft7, properties_default) {
   EXPECT_EQ(document, expected);
 }
 
-TEST(Lint_draft7, pattern_properties_default) {
+TEST(Lint_draft7, pattern_properties_default_1) {
   sourcemeta::jsontoolkit::JSON document =
       sourcemeta::jsontoolkit::parse(R"JSON({
     "$schema": "http://json-schema.org/draft-07/schema#",