diff --git a/src/parser.ts b/src/parser.ts
index 50f29b9e..4b50a98f 100644
--- a/src/parser.ts
+++ b/src/parser.ts
@@ -20,6 +20,7 @@ import {
   isPrimitive,
   JSONSchema as LinkedJSONSchema,
   JSONSchemaWithDefinitions,
+  NormalizedJSONSchema,
   SchemaSchema,
   SchemaType
 } from './types/JSONSchema'
@@ -313,9 +314,19 @@ function newInterface(
   usedNames: UsedNames,
   keyName?: string,
   keyNameFromDefinition?: string
-): TInterface {
+): TInterface | TIntersection {
+  let complexAdditionalProperties: false | NormalizedJSONSchema
+
+  if (schema.additionalProperties !== undefined && typeof schema.additionalProperties !== 'boolean') {
+    complexAdditionalProperties = schema.additionalProperties
+    schema.additionalProperties = false
+  } else {
+    complexAdditionalProperties = false
+  }
+
   const name = standaloneName(schema, keyNameFromDefinition, usedNames)!
-  return {
+
+  const parsedInterface: TInterface = {
     comment: schema.description,
     keyName,
     params: parseSchema(schema, options, processed, usedNames, name),
@@ -323,6 +334,43 @@ function newInterface(
     superTypes: parseSuperTypes(schema, options, processed, usedNames),
     type: 'INTERFACE'
   }
+
+  if (complexAdditionalProperties === false) {
+    return parsedInterface
+  } else {
+    const parsedAdditionalProperties: TInterface = {
+      params: [
+        {
+          ast: parse(complexAdditionalProperties, options, '[k: string]', processed, usedNames),
+          isPatternProperty: false,
+          isRequired: true,
+          isUnreachableDefinition: false,
+          keyName: '[k: string]'
+        }
+      ],
+      superTypes: [],
+      type: 'INTERFACE'
+    }
+
+    if (parsedInterface.params.length > 0) {
+      delete parsedInterface.standaloneName
+      return {
+        comment: schema.description,
+        keyName,
+        standaloneName: name,
+        params: [parsedInterface, parsedAdditionalProperties],
+        type: 'INTERSECTION'
+      }
+    } else {
+      // there were only additionalProperties
+      return {
+        ...parsedAdditionalProperties,
+        comment: schema.description,
+        keyName,
+        standaloneName: name
+      }
+    }
+  }
 }
 
 function parseSuperTypes(
diff --git a/test/__snapshots__/test/test.ts.md b/test/__snapshots__/test/test.ts.md
index d9e34739..43a0e5e2 100644
--- a/test/__snapshots__/test/test.ts.md
+++ b/test/__snapshots__/test/test.ts.md
@@ -115,10 +115,11 @@ Generated by [AVA](https://avajs.dev).
      * and run json-schema-to-typescript to regenerate this file.␊
      */␊
     ␊
-    export interface AdditionalProperties {␊
+    export type AdditionalProperties = {␊
       foo?: string;␊
+    } & {␊
       [k: string]: number;␊
-    }␊
+    };␊
     `
 
 ## additionalProperties.2.js
@@ -1271,6 +1272,15 @@ Generated by [AVA](https://avajs.dev).
       [k: string]: unknown;␊
     };␊
     export type Header1 = ExampleXORExamples & SchemaXORContent;␊
+    export type Callback = {␊
+      /**␊
+       * This interface was referenced by \`Callback\`'s JSON-Schema definition␊
+       * via the \`patternProperty\` "^x-".␊
+       */␊
+      [k: string]: unknown;␊
+    } & {␊
+      [k: string]: PathItem;␊
+    };␊
     export type SecurityScheme =␊
       | APIKeySecurityScheme␊
       | HTTPSecurityScheme␊
@@ -1579,9 +1589,6 @@ Generated by [AVA](https://avajs.dev).
        */␊
       [k: string]: unknown;␊
     }␊
-    export interface Callback {␊
-      [k: string]: PathItem;␊
-    }␊
     export interface Components {␊
       schemas?: {␊
         /**␊
@@ -2132,10 +2139,11 @@ Generated by [AVA](https://avajs.dev).
      * and run json-schema-to-typescript to regenerate this file.␊
      */␊
     ␊
-    export interface StrictIndexSignatures {␊
+    export type StrictIndexSignatures = {␊
       maybe?: string;␊
+    } & {␊
       [k: string]: string | undefined;␊
-    }␊
+    };␊
     `
 
 ## options.style.js
@@ -2326,15 +2334,16 @@ Generated by [AVA](https://avajs.dev).
      * and run json-schema-to-typescript to regenerate this file.␊
      */␊
     ␊
+    export type Parent = {␊
+      [k: string]: StringChild;␊
+    } & {␊
+      [k: string]: number;␊
+    };␊
     /**␊
      * This interface was referenced by \`Parent\`'s JSON-Schema definition␊
      * via the \`patternProperty\` "^[a-zA-Z]+".␊
      */␊
     export type StringChild = string;␊
-    ␊
-    export interface Parent {␊
-      [k: string]: number;␊
-    }␊
     `
 
 ## realWorld.awsQuicksight.js
@@ -444063,6 +444072,15 @@ Generated by [AVA](https://avajs.dev).
       [k: string]: unknown;␊
     };␊
     export type Header1 = ExampleXORExamples & SchemaXORContent;␊
+    export type Callback = {␊
+      /**␊
+       * This interface was referenced by \`Callback\`'s JSON-Schema definition␊
+       * via the \`patternProperty\` "^x-".␊
+       */␊
+      [k: string]: unknown;␊
+    } & {␊
+      [k: string]: PathItem;␊
+    };␊
     export type SecurityScheme =␊
       | APIKeySecurityScheme␊
       | HTTPSecurityScheme␊
@@ -444371,9 +444389,6 @@ Generated by [AVA](https://avajs.dev).
        */␊
       [k: string]: unknown;␊
     }␊
-    export interface Callback {␊
-      [k: string]: PathItem;␊
-    }␊
     export interface Components {␊
       schemas?: {␊
         /**␊
@@ -447709,6 +447724,7 @@ Generated by [AVA](https://avajs.dev).
         prerestart?: ScriptsRestart;␊
         restart?: ScriptsRestart;␊
         postrestart?: ScriptsRestart;␊
+      } & {␊
         [k: string]: string | undefined;␊
       };␊
       /**␊
@@ -447749,6 +447765,7 @@ Generated by [AVA](https://avajs.dev).
       };␊
       engines?: {␊
         node?: string;␊
+      } & {␊
         [k: string]: string;␊
       };␊
       engineStrict?: boolean;␊
@@ -447789,11 +447806,12 @@ Generated by [AVA](https://avajs.dev).
        */␊
       esnext?:␊
         | string␊
-        | {␊
+        | ({␊
             main?: string;␊
             browser?: string;␊
+          } & {␊
             [k: string]: string;␊
-          };␊
+          });␊
       /**␊
        * Allows packages within a directory to depend on one another using direct linking of local files. Additionally, dependencies within a workspace are hoisted to the workspace root when possible to reduce duplication. Note: It's also a good idea to set "private" to true when using this feature.␊
        */␊
@@ -448598,6 +448616,7 @@ Generated by [AVA](https://avajs.dev).
         company?: {␊
           name: string;␊
         };␊
+      } & {␊
         [k: string]: KString;␊
       };␊
       [k: string]: unknown;␊
diff --git a/test/__snapshots__/test/test.ts.snap b/test/__snapshots__/test/test.ts.snap
index cd1fb9ed..6b793eb3 100644
Binary files a/test/__snapshots__/test/test.ts.snap and b/test/__snapshots__/test/test.ts.snap differ