diff --git a/packages/ruleset/src/functions/inline-schema-rules.js b/packages/ruleset/src/functions/inline-schema-rules.js
index fffa47d22..6599c9510 100644
--- a/packages/ruleset/src/functions/inline-schema-rules.js
+++ b/packages/ruleset/src/functions/inline-schema-rules.js
@@ -3,7 +3,7 @@ const {
   isJsonMimeType,
   isArraySchema,
   isEmptyObjectSchema,
-  isPrimitiveType,
+  isPrimitiveSchema,
   isRefSiblingSchema,
   validateSubschemas
 } = require('../utils');
@@ -35,7 +35,7 @@ function inlineResponseSchema(schema, options, { path }) {
   if (
     !schema.$ref &&
     isJsonMimeType(mimeType) &&
-    !isPrimitiveType(schema) &&
+    !isPrimitiveSchema(schema) &&
     !arrayItemsAreRefOrPrimitive(schema) &&
     !isRefSiblingSchema(schema)
   ) {
@@ -72,7 +72,7 @@ function inlineRequestSchema(schema, options, { path }) {
   if (
     !schema.$ref &&
     isJsonMimeType(mimeType) &&
-    !isPrimitiveType(schema) &&
+    !isPrimitiveSchema(schema) &&
     !arrayItemsAreRefOrPrimitive(schema) &&
     !isRefSiblingSchema(schema)
   ) {
@@ -111,9 +111,11 @@ function inlineRequestSchema(schema, options, { path }) {
  * @returns an array containing the violations found or [] if no violations
  */
 function inlinePropertySchema(schema, options, { path }) {
-  // Check each sub-schema that is reachable from "schema" (properties,
-  // additionalProperties, allOf/anyOf/oneOf, array items, etc.) .
-  return validateSubschemas(schema, path, checkForInlineNestedObjectSchema);
+  // If "schema" is not a primitive, then check each sub-schema that is reachable from
+  // "schema" (properties, additionalProperties, allOf/anyOf/oneOf, array items, etc.).
+  return isPrimitiveSchema(schema)
+    ? []
+    : validateSubschemas(schema, path, checkForInlineNestedObjectSchema);
 }
 
 /**
@@ -129,7 +131,7 @@ function checkForInlineNestedObjectSchema(schema, path) {
   // then bail out now to avoid a warning.
   if (
     schema.$ref ||
-    isPrimitiveType(schema) ||
+    isPrimitiveSchema(schema) ||
     isRefSiblingSchema(schema) ||
     isEmptyObjectSchema(schema) ||
     isArraySchema(schema)
@@ -182,5 +184,5 @@ function checkForInlineNestedObjectSchema(schema, path) {
 function arrayItemsAreRefOrPrimitive(schema) {
   const isArray = isArraySchema(schema);
   const items = isArray && getCompositeSchemaAttribute(schema, 'items');
-  return items && (items.$ref || isPrimitiveType(items));
+  return items && (items.$ref || isPrimitiveSchema(items));
 }
diff --git a/packages/ruleset/src/utils/get-schema-type.js b/packages/ruleset/src/utils/get-schema-type.js
index 85dbee9d5..1eb9b09eb 100644
--- a/packages/ruleset/src/utils/get-schema-type.js
+++ b/packages/ruleset/src/utils/get-schema-type.js
@@ -294,6 +294,21 @@ const isStringSchema = schema => {
   return checkCompositeSchemaForConstraint(schema, s => s.type === 'string');
 };
 
+/**
+ * Returns `true` for a primitive schema (anything encoded as a JSON string, number, or boolean).
+ *
+ * @param {object} schema - Simple or composite OpenAPI 3.0 schema object.
+ * @returns {boolean}
+ */
+const isPrimitiveSchema = schema => {
+  // This implementation should remain stable when additional specific types are added
+  return (
+    !isObjectSchema(schema) &&
+    !isArraySchema(schema) &&
+    getSchemaType(schema) !== SchemaType.UNKNOWN
+  );
+};
+
 module.exports = {
   SchemaType,
   getSchemaType,
@@ -311,5 +326,6 @@ module.exports = {
   isIntegerSchema,
   isNumberSchema,
   isObjectSchema,
+  isPrimitiveSchema,
   isStringSchema
 };
diff --git a/packages/ruleset/src/utils/index.js b/packages/ruleset/src/utils/index.js
index 5318c3036..6cad71835 100644
--- a/packages/ruleset/src/utils/index.js
+++ b/packages/ruleset/src/utils/index.js
@@ -6,7 +6,6 @@ module.exports = {
   isDeprecated: require('./is-deprecated'),
   isEmptyObjectSchema: require('./is-empty-object-schema'),
   isObject: require('./is-object'),
-  isPrimitiveType: require('./is-primitive-type'),
   isRefSiblingSchema: require('./is-ref-sibling-schema'),
   mergeAllOfSchemaProperties: require('./merge-allof-schema-properties'),
   ...require('./mimetype-utils'),
diff --git a/packages/ruleset/src/utils/is-primitive-type.js b/packages/ruleset/src/utils/is-primitive-type.js
deleted file mode 100644
index d708e932b..000000000
--- a/packages/ruleset/src/utils/is-primitive-type.js
+++ /dev/null
@@ -1,13 +0,0 @@
-/**
- * Returns true if "schema" is a primitive schema.
- * @param {*} schema the schema to check
- * @returns boolean
- */
-function isPrimitiveType(schema) {
-  return (
-    schema.type &&
-    ['boolean', 'integer', 'number', 'string'].includes(schema.type)
-  );
-}
-
-module.exports = isPrimitiveType;
diff --git a/packages/ruleset/test/inline-property-schema.test.js b/packages/ruleset/test/inline-property-schema.test.js
index 952f66af2..0af8bddb5 100644
--- a/packages/ruleset/test/inline-property-schema.test.js
+++ b/packages/ruleset/test/inline-property-schema.test.js
@@ -49,6 +49,24 @@ describe('Spectral rule: inline-property-schema', () => {
       const results = await testRule(ruleId, rule, testDocument);
       expect(results).toHaveLength(0);
     });
+
+    it('Composed primitive schema', async () => {
+      const testDocument = makeCopy(rootDocument);
+
+      testDocument.components.schemas.Car.properties['inline_prop'] = {
+        oneOf: [
+          {
+            type: 'string'
+          },
+          {
+            type: 'string'
+          }
+        ]
+      };
+
+      const results = await testRule(ruleId, rule, testDocument);
+      expect(results).toHaveLength(0);
+    });
   });
 
   describe('Should yield errors', () => {
diff --git a/packages/ruleset/test/inline-request-schema.test.js b/packages/ruleset/test/inline-request-schema.test.js
index 7d347384e..74edb41ba 100644
--- a/packages/ruleset/test/inline-request-schema.test.js
+++ b/packages/ruleset/test/inline-request-schema.test.js
@@ -107,6 +107,26 @@ describe('Spectral rule: inline-request-schema', () => {
       const results = await testRule(ruleId, rule, testDocument);
       expect(results).toHaveLength(0);
     });
+
+    it('Composed primitive schema', async () => {
+      const testDocument = makeCopy(rootDocument);
+
+      testDocument.paths['/v1/drinks'].post.requestBody.content[
+        'application/json'
+      ].schema = {
+        oneOf: [
+          {
+            type: 'string'
+          },
+          {
+            type: 'string'
+          }
+        ]
+      };
+
+      const results = await testRule(ruleId, rule, testDocument);
+      expect(results).toHaveLength(0);
+    });
   });
 
   describe('Should yield errors', () => {
diff --git a/packages/ruleset/test/inline-response-schema.test.js b/packages/ruleset/test/inline-response-schema.test.js
index 2df5286fe..8463a6de4 100644
--- a/packages/ruleset/test/inline-response-schema.test.js
+++ b/packages/ruleset/test/inline-response-schema.test.js
@@ -137,6 +137,26 @@ describe('Spectral rule: inline-response-schema', () => {
       const results = await testRule(ruleId, rule, testDocument);
       expect(results).toHaveLength(0);
     });
+
+    it('Composed primitive schema', async () => {
+      const testDocument = makeCopy(rootDocument);
+
+      testDocument.paths['/v1/movies'].post.responses['201'].content[
+        'application/json'
+      ].schema = {
+        oneOf: [
+          {
+            type: 'string'
+          },
+          {
+            type: 'string'
+          }
+        ]
+      };
+
+      const results = await testRule(ruleId, rule, testDocument);
+      expect(results).toHaveLength(0);
+    });
   });
 
   describe('Should yield errors', () => {
diff --git a/packages/ruleset/test/is-object-schema.test.js b/packages/ruleset/test/is-object-schema.test.js
index 833a6ae54..b82ddc625 100644
--- a/packages/ruleset/test/is-object-schema.test.js
+++ b/packages/ruleset/test/is-object-schema.test.js
@@ -58,4 +58,34 @@ describe('Utility function: isObjectSchema()', () => {
       })
     ).toBe(true);
   });
+
+  it('should recurse through `oneOf` and `allOf` (implicit object type)', async () => {
+    expect(
+      isObjectSchema({
+        oneOf: [
+          {
+            allOf: [{ properties: {} }, {}]
+          },
+          {
+            properties: {}
+          }
+        ]
+      })
+    ).toBe(true);
+  });
+
+  it('should recurse through `allOf` (implicit object type)', async () => {
+    expect(
+      isObjectSchema({
+        allOf: [
+          {
+            allOf: [{ properties: {} }, {}]
+          },
+          {
+            properties: {}
+          }
+        ]
+      })
+    ).toBe(true);
+  });
 });
diff --git a/packages/ruleset/test/is-primitive-schema.test.js b/packages/ruleset/test/is-primitive-schema.test.js
new file mode 100644
index 000000000..6f552d3de
--- /dev/null
+++ b/packages/ruleset/test/is-primitive-schema.test.js
@@ -0,0 +1,142 @@
+const { isPrimitiveSchema } = require('../src/utils');
+
+describe('Utility function: isPrimitiveSchema()', () => {
+  it('should return `false` for `undefined`', async () => {
+    expect(isPrimitiveSchema(undefined)).toBe(false);
+  });
+
+  it('should return `false` for `null`', async () => {
+    expect(isPrimitiveSchema(null)).toBe(false);
+  });
+
+  it('should return `false` for an array', async () => {
+    expect(isPrimitiveSchema([])).toBe(false);
+  });
+
+  it('should return `false` for an empty object', async () => {
+    expect(isPrimitiveSchema({})).toBe(false);
+  });
+
+  it('should return `true` for a boolean schema', async () => {
+    expect(isPrimitiveSchema({ type: 'boolean' })).toBe(true);
+  });
+
+  it('should return `true` for a byte schema', async () => {
+    expect(isPrimitiveSchema({ type: 'string', format: 'byte' })).toBe(true);
+  });
+
+  it('should return `true` for a double schema', async () => {
+    expect(isPrimitiveSchema({ type: 'number', format: 'double' })).toBe(true);
+  });
+
+  it('should return `true` for an enumeration', async () => {
+    expect(isPrimitiveSchema({ type: 'string', enum: ['foo', 'bar'] })).toBe(
+      true
+    );
+  });
+
+  it('should return `true` for a float schema', async () => {
+    expect(isPrimitiveSchema({ type: 'number', format: 'float' })).toBe(true);
+  });
+
+  it('should return `true` for a int32 schema', async () => {
+    expect(isPrimitiveSchema({ type: 'integer', format: 'int32' })).toBe(true);
+  });
+
+  it('should return `true` for a int64 schema', async () => {
+    expect(isPrimitiveSchema({ type: 'integer', format: 'int64' })).toBe(true);
+  });
+
+  it('should return `true` for a integer schema', async () => {
+    expect(isPrimitiveSchema({ type: 'integer' })).toBe(true);
+  });
+
+  it('should return `true` for a number schema', async () => {
+    expect(isPrimitiveSchema({ type: 'number' })).toBe(true);
+  });
+
+  it('should return `true` for a string schema', async () => {
+    expect(isPrimitiveSchema({ type: 'string' })).toBe(true);
+  });
+
+  it('should return true for a composed schema that resolves to "int32"', async () => {
+    expect(
+      isPrimitiveSchema({
+        oneOf: [
+          {
+            allOf: [
+              {
+                anyOf: [
+                  { type: 'integer', format: 'int32' },
+                  { type: 'integer', format: 'int32' }
+                ]
+              },
+              {}
+            ]
+          },
+          { type: 'integer', format: 'int32' }
+        ]
+      })
+    ).toBe(true);
+  });
+
+  it('should return true for a composed schema that resolves to "double"', async () => {
+    expect(
+      isPrimitiveSchema({
+        oneOf: [
+          {
+            allOf: [
+              {
+                anyOf: [
+                  { type: 'number', format: 'double' },
+                  { type: 'number', format: 'double' }
+                ]
+              },
+              {}
+            ]
+          },
+          { type: 'number', format: 'double' }
+        ]
+      })
+    ).toBe(true);
+  });
+
+  it('should return true for a composed schema that resolves to "number"', async () => {
+    expect(
+      isPrimitiveSchema({
+        oneOf: [
+          {
+            allOf: [{ anyOf: [{ type: 'number' }, { type: 'number' }] }, {}]
+          },
+          { type: 'number' }
+        ]
+      })
+    ).toBe(true);
+  });
+
+  it('should return true for a composed schema that resolves to "boolean"', async () => {
+    expect(
+      isPrimitiveSchema({
+        oneOf: [
+          {
+            allOf: [{ anyOf: [{ type: 'boolean' }, { type: 'boolean' }] }, {}]
+          },
+          { type: 'boolean' }
+        ]
+      })
+    ).toBe(true);
+  });
+
+  it('should return true for a composed schema that resolves to "string"', async () => {
+    expect(
+      isPrimitiveSchema({
+        oneOf: [
+          {
+            allOf: [{ anyOf: [{ type: 'string' }, { type: 'string' }] }, {}]
+          },
+          { type: 'string' }
+        ]
+      })
+    ).toBe(true);
+  });
+});