diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java
index 26b91464f898..3f52424b6170 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConfig.java
@@ -174,6 +174,8 @@ public interface CodegenConfig {
 
     String toModelImport(String name);
 
+    Map<String,String> toModelImportMap(String name);
+
     String toApiImport(String name);
 
     void addOperationToGroup(String tag, String resourcePath, Operation operation, CodegenOperation co, Map<String, List<CodegenOperation>> operations);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 92a3f76b7600..bba1b9825f9e 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -22,6 +22,7 @@
 import com.github.benmanes.caffeine.cache.Ticker;
 import com.google.common.base.CaseFormat;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
 import com.samskivert.mustache.Mustache;
 import com.samskivert.mustache.Mustache.Compiler;
 import com.samskivert.mustache.Mustache.Lambda;
@@ -1367,6 +1368,16 @@ public String toModelImport(String name) {
         }
     }
 
+    /**
+     * Returns the same content as [[toModelImport]] with key the fully-qualified Model name and value the initial input.
+     * In case of union types this method has a key for each separate model and import.
+     * @param name the name of the "Model"
+     * @return Map of fully-qualified models.
+     */
+    public Map<String,String> toModelImportMap(String name){
+        return Collections.singletonMap(this.toModelImport(name),name);
+    }
+
     /**
      * Return the fully-qualified "Api" name for import
      *
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
index ee7b50c05c73..c73e1f5fb131 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
@@ -58,6 +58,7 @@
 import java.nio.file.Path;
 import java.time.ZonedDateTime;
 import java.util.*;
+import java.util.stream.Collectors;
 
 import static org.openapitools.codegen.utils.OnceLogger.once;
 
@@ -1077,26 +1078,11 @@ private Map<String, Object> processOperations(CodegenConfig config, String tag,
             allImports.addAll(op.imports);
         }
 
-        List<Map<String, String>> imports = new ArrayList<>();
-        Set<String> mappingSet = new TreeSet<>();
-        for (String nextImport : allImports) {
-            Map<String, String> im = new LinkedHashMap<>();
-            String mapping = config.importMapping().get(nextImport);
-            if (mapping == null) {
-                mapping = config.toModelImport(nextImport);
-            }
+        Map<String,String> mappings = getAllImportsMappings(allImports);
+        Set<Map<String, String>> imports = toImportsObjects(mappings);
 
-            if (mapping != null && !mappingSet.contains(mapping)) { // ensure import (mapping) is unique
-                mappingSet.add(mapping);
-                im.put("import", mapping);
-                im.put("classname", nextImport);
-                if (!imports.contains(im)) { // avoid duplicates
-                    imports.add(im);
-                }
-            }
-        }
-
-        operations.put("imports", imports);
+        //Some codegen implementations rely on a list interface for the imports
+        operations.put("imports", imports.stream().collect(Collectors.toList()));
 
         // add a flag to indicate whether there's any {{import}}
         if (imports.size() > 0) {
@@ -1115,6 +1101,49 @@ private Map<String, Object> processOperations(CodegenConfig config, String tag,
         return operations;
     }
 
+    /**
+     * Transforms a set of imports to a map with key config.toModelImport(import) and value the import string.
+     * @param allImports - Set of imports
+     * @return Map of fully qualified import path and initial import.
+     */
+    private Map<String,String> getAllImportsMappings(Set<String> allImports){
+        Map<String,String> result = new HashMap<>();
+        allImports.forEach(nextImport->{
+            String mapping = config.importMapping().get(nextImport);
+            if(mapping!= null){
+                result.put(mapping,nextImport);
+            }else{
+                result.putAll(config.toModelImportMap(nextImport));
+            }
+        });
+        return result;
+    }
+
+    /**
+     * Using an import map created via {@link #getAllImportsMappings(Set)} to build a list import objects.
+     * The import objects have two keys: import and classname which hold the key and value of the initial map entry.
+     *
+     * @param mappedImports Map of fully qualified import and import
+     * @return The set of unique imports
+     */
+    private Set<Map<String,String>> toImportsObjects(Map<String,String> mappedImports){
+        Set<Map<String, String>> result = new TreeSet<Map<String,String>>(
+            (Comparator<Map<String, String>>) (o1, o2) -> {
+                String s1 = o1.get("classname");
+                String s2 = o2.get("classname");
+                return s1.compareTo(s2);
+            }
+        );
+
+        mappedImports.entrySet().forEach(mapping->{
+            Map<String, String> im = new LinkedHashMap<>();
+            im.put("import", mapping.getKey());
+            im.put("classname", mapping.getValue());
+            result.add(im);
+        });
+        return result;
+     }
+
     private Map<String, Object> processModels(CodegenConfig config, Map<String, Schema> definitions) {
         Map<String, Object> objs = new HashMap<>();
         objs.put("package", config.modelPackage());
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
index bbc8e459fe3a..7cd75706b27d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
@@ -17,6 +17,8 @@
 
 package org.openapitools.codegen.languages;
 
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.ComposedSchema;
@@ -35,6 +37,7 @@
 import java.io.File;
 import java.text.SimpleDateFormat;
 import java.util.*;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
@@ -224,6 +227,47 @@ public void processOpts() {
         }
     }
 
+    @Override
+    public String toModelImport( String name){
+        if(isUnionType(name)){
+           LOGGER.warn("The import is a union type. Consider using the toModelImportMap method.");
+           return toModelImportMap(name).values().stream().collect(Collectors.joining("|"));
+        }
+        return super.toModelImport(name);
+    }
+
+    /**
+     * Maps the fully qualified model import to the initial given name. In case of union types the map will have multiple entries.
+     * For example for "classA | classB" the map will two entries have ["model.classA","classA"] and ["model.classB","classB"].
+     *
+     * @param name the name of the "Model"
+     * @return Map between the fully qualified model import and the initial given name.
+     */
+    @Override
+    public Map<String,String> toModelImportMap( String name){
+        if(isUnionType(name)){
+           String[] names = splitUnionType(name);
+           return toImportMap(names);
+        }
+        return toImportMap(name);
+    }
+
+    private boolean isUnionType(String name){
+        return name.contains("|");
+    }
+
+    private String[] splitUnionType(String name){
+        return  name.replace(" ","").split("\\|");
+    }
+
+    private Map<String,String> toImportMap(String... names){
+        Map<String,String> result = Maps.newHashMap();
+        for(String name: names){
+            result.put(toModelImport(name),name);
+        }
+        return result;
+    }
+
     @Override
     public void preprocessOpenAPI(OpenAPI openAPI) {
 
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/SharedTypeScriptTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/SharedTypeScriptTest.java
new file mode 100644
index 000000000000..9062d738689b
--- /dev/null
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/SharedTypeScriptTest.java
@@ -0,0 +1,72 @@
+package org.openapitools.codegen.typescript;
+
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.openapitools.codegen.DefaultGenerator;
+import org.openapitools.codegen.Generator;
+import org.openapitools.codegen.config.CodegenConfigurator;
+import org.openapitools.codegen.languages.TypeScriptAxiosClientCodegen;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.List;
+
+public class SharedTypeScriptTest {
+    @Test
+    public void typesInImportsAreSplittedTest() throws IOException {
+        CodegenConfigurator config =
+                new CodegenConfigurator()
+                        .setInputSpec("src/test/resources/split-import.json")
+                        .setModelPackage("model")
+                        .setApiPackage("api")
+                        .setOutputDir("src/test/resources/typesInImportsAreSplittedTest")
+                        .addAdditionalProperty(
+                                TypeScriptAxiosClientCodegen.SEPARATE_MODELS_AND_API, true);
+
+        config.setGeneratorName("typescript-axios");
+        checkAPIFile(getGenerator(config).generate(), "default-api.ts");
+
+        config.setGeneratorName("typescript-node");
+        checkAPIFile(getGenerator(config).generate(), "defaultApi.ts");
+
+        config.setGeneratorName("typescript-angular");
+        checkAPIFile(getGenerator(config).generate(), "default.service.ts");
+
+        FileUtils.deleteDirectory(new File("src/test/resources/typesInImportsAreSplittedTest"));
+    }
+
+    private Generator getGenerator(CodegenConfigurator config) {
+        return new DefaultGenerator().opts(config.toClientOptInput());
+    }
+
+    private void checkAPIFile(List<File> files, String apiFileName) throws IOException {
+        File apiFile = files.stream().filter(file->file.getName().contains(apiFileName)).findFirst().get();
+        String apiFileContent = FileUtils.readFileToString(apiFile);
+        Assert.assertTrue(!apiFileContent.contains("import { OrganizationWrapper | PersonWrapper }"));
+        Assert.assertEquals(StringUtils.countMatches(apiFileContent,"import { PersonWrapper }"),1);
+        Assert.assertEquals(StringUtils.countMatches(apiFileContent,"import { OrganizationWrapper }"),1);
+    }
+
+    @Test
+    public void oldImportsStillPresentTest() throws IOException {
+        CodegenConfigurator config =
+                new CodegenConfigurator()
+                        .setInputSpec("petstore.json")
+                        .setModelPackage("model")
+                        .setApiPackage("api")
+                        .setOutputDir("src/test/resources/oldImportsStillPresentTest/")
+                        .addAdditionalProperty(
+                                TypeScriptAxiosClientCodegen.SEPARATE_MODELS_AND_API, true);
+
+        config.setGeneratorName("typescript-angular");
+        final List<File> files = getGenerator(config).generate();
+        File pets = files.stream().filter(file->file.getName().contains("pet.ts")).findFirst().get();
+        String apiFileContent = FileUtils.readFileToString(pets);
+        Assert.assertTrue(apiFileContent.contains("import { Category }"));
+        Assert.assertTrue(apiFileContent.contains("import { Tag }"));
+
+        FileUtils.deleteDirectory(new File("src/test/resources/oldImportsStillPresentTest/"));
+    }
+}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/test/resources/split-import.json b/modules/openapi-generator/src/test/resources/split-import.json
new file mode 100644
index 000000000000..736517af4635
--- /dev/null
+++ b/modules/openapi-generator/src/test/resources/split-import.json
@@ -0,0 +1,74 @@
+{
+  "openapi": "3.0.2",
+  "info": {
+    "title": "SAP Graph - Customers API",
+    "version": "0.1.0"
+  },
+  "paths": {
+    "/Customer": {
+      "get": {
+        "operationId": "getCustomer",
+        "responses": {
+          "200": {
+            "$ref": "#/components/responses/CustomerResponse"
+          }
+        }
+      }
+    },
+    "/Person": {
+      "get": {
+        "operationId": "getPerson",
+        "responses": {
+          "200": {
+            "$ref": "#/components/responses/PersonResponse"
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "OrganizationWrapper": {
+        "type": "object",
+        "properties": {
+          "id":  {"type": "string"}
+        }
+      },
+      "PersonWrapper": {
+        "type": "object",
+        "properties": {
+          "id":  {"type": "string"}
+        }
+      }
+    },
+    "responses": {
+      "CustomerResponse": {
+        "description": "Get Customer",
+        "content": {
+          "application/json": {
+            "schema": {
+              "oneOf": [
+                {
+                  "$ref": "#/components/schemas/OrganizationWrapper"
+                },
+                {
+                  "$ref": "#/components/schemas/PersonWrapper"
+                }
+              ]
+            }
+          }
+        }
+      },
+      "PersonResponse": {
+        "description": "Get Person",
+        "content": {
+          "application/json": {
+            "schema": {
+              "$ref": "#/components/schemas/PersonWrapper"
+            }
+          }
+        }
+      }
+    }
+  }
+}