diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java
index 21e7d80d7ab..68ed111f964 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java
@@ -21,6 +21,8 @@ import com.samskivert.mustache.Escapers;
 import com.samskivert.mustache.Mustache;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.Schema;
+import io.swagger.v3.oas.models.media.StringSchema;
+
 import org.apache.commons.io.FilenameUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.openapitools.codegen.*;
@@ -354,16 +356,21 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
-            ArraySchema ap = (ArraySchema) p;
-            Schema inner = ap.getItems();
-            return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
-            Schema inner = getAdditionalProperties(p);
-
-            return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
+        Schema<?> schema = ModelUtils.unaliasSchema(this.openAPI, p, importMapping);
+        Schema<?> target = ModelUtils.isGenerateAliasAsModel() ? p : schema;
+        if (ModelUtils.isArraySchema(target)) {
+            Schema<?> items = getSchemaItems((ArraySchema) schema);
+            return getSchemaType(target) + "[" + getTypeDeclaration(items) + "]";
+        } else if (ModelUtils.isMapSchema(target)) {
+            Schema<?> inner = getAdditionalProperties(target);
+            if (inner == null) {
+                LOGGER.error("`{}` (map property) does not have a proper inner type defined. Default to type:string", p.getName());
+                inner = new StringSchema().description("TODO default missing map inner type to string");
+                p.setAdditionalProperties(inner);
+            }
+            return getSchemaType(target) + "[String, " + getTypeDeclaration(inner) + "]";
         }
-        return super.getTypeDeclaration(p);
+        return super.getTypeDeclaration(target);
     }
 
     @Override
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/scala/AbstractScalaCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/scala/AbstractScalaCodegenTest.java
index ce62184a0d3..b320251de3d 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/scala/AbstractScalaCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/scala/AbstractScalaCodegenTest.java
@@ -1,9 +1,16 @@
 package org.openapitools.codegen.scala;
 
+import io.swagger.v3.oas.models.Components;
+import io.swagger.v3.oas.models.OpenAPI;
+import io.swagger.v3.oas.models.media.ArraySchema;
+import io.swagger.v3.oas.models.media.MapSchema;
 import io.swagger.v3.oas.models.media.ObjectSchema;
 import io.swagger.v3.oas.models.media.Schema;
+import io.swagger.v3.oas.models.media.StringSchema;
+
 import org.openapitools.codegen.CodegenConstants;
 import org.openapitools.codegen.languages.AbstractScalaCodegen;
+import org.openapitools.codegen.utils.ModelUtils;
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
@@ -99,19 +106,28 @@ public class AbstractScalaCodegenTest {
     }
 
     @Test
-    void checkScalaTypeDeclaration() {
-
-        final AbstractScalaCodegen codegen = new P_AbstractScalaCodegen();
-
+    void checkTypeDeclarationWithByteString() {
         Schema<?> byteArraySchema = new ObjectSchema();
         byteArraySchema.setType("string");
         byteArraySchema.setFormat("byte");
         byteArraySchema.setDescription("Schema with byte string");
 
-        Assert.assertEquals(codegen.getTypeDeclaration(byteArraySchema), "Array[Byte]",
+        Assert.assertEquals(fakeScalaCodegen.getTypeDeclaration(byteArraySchema), "Array[Byte]",
                 "OpenApi File type represented as byte string should be represented as Array[Byte] scala type");
-
     }
 
+    @Test
+    void checkTypeDeclarationWithStringToArrayModelMapping() {
+        // Create an alias to an array schema
+        final Schema<?> nestedArraySchema = new ArraySchema().items(new StringSchema());
+        // Create a map schema with additionalProperties type set to array alias
+        final Schema<?> mapSchema = new MapSchema().additionalProperties(new Schema().$ref("#/components/schemas/NestedArray"));
+        fakeScalaCodegen.setOpenAPI(new OpenAPI().components(new Components().addSchemas("NestedArray", nestedArraySchema)));
 
+        ModelUtils.setGenerateAliasAsModel(false);
+        Assert.assertEquals(fakeScalaCodegen.getTypeDeclaration(mapSchema), "Map[String, List[String]]");
+
+        ModelUtils.setGenerateAliasAsModel(true);
+        Assert.assertEquals(fakeScalaCodegen.getTypeDeclaration(mapSchema), "Map[String, NestedArray]");
+    }
 }