diff --git a/docs/generators/swift5.md b/docs/generators/swift5.md
index 7c3052b6e4c9..d04ae8e878e0 100644
--- a/docs/generators/swift5.md
+++ b/docs/generators/swift5.md
@@ -113,45 +113,92 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>#line</li>
 <li>#selector</li>
 <li>#sourceLocation</li>
+<li>APIHelper</li>
+<li>AlamofireDecodableRequestBuilder</li>
+<li>AlamofireRequestBuilder</li>
+<li>AlamofireRequestBuilderFactory</li>
 <li>Any</li>
+<li>AnyHashable</li>
 <li>AnyObject</li>
+<li>AnyResponseSerializer</li>
 <li>Array</li>
+<li>ArrayRule</li>
+<li>ArrayValidationErrorKind</li>
 <li>Bool</li>
 <li>COLUMN</li>
+<li>Calendar</li>
+<li>CaseIterableDefaultsLast</li>
 <li>Character</li>
 <li>Class</li>
 <li>ClosedRange</li>
 <li>Codable</li>
+<li>CodableHelper</li>
+<li>Configuration</li>
 <li>CountableClosedRange</li>
 <li>CountableRange</li>
 <li>Data</li>
+<li>DateFormatter</li>
 <li>Decodable</li>
+<li>DecodableRequestBuilderError</li>
 <li>Dictionary</li>
+<li>DispatchQueue</li>
 <li>Double</li>
+<li>DownloadException</li>
 <li>Encodable</li>
 <li>Error</li>
 <li>ErrorResponse</li>
 <li>FILE</li>
 <li>FUNCTION</li>
+<li>FileManager</li>
 <li>Float</li>
 <li>Float32</li>
 <li>Float64</li>
 <li>Float80</li>
+<li>HTTPMethod</li>
+<li>HTTPURLResponse</li>
 <li>Int</li>
 <li>Int16</li>
 <li>Int32</li>
 <li>Int64</li>
 <li>Int8</li>
+<li>JSONDataEncoding</li>
+<li>JSONDecoder</li>
+<li>JSONEncodable</li>
+<li>JSONEncoder</li>
+<li>JSONEncodingHelper</li>
+<li>KeyedDecodingContainerProtocol</li>
+<li>KeyedEncodingContainerProtocol</li>
 <li>LINE</li>
+<li>Locale</li>
+<li>NSCoder</li>
+<li>NSDecimalNumber</li>
+<li>NSNumber</li>
+<li>NSObject</li>
+<li>NSRecursiveLock</li>
+<li>NSRegularExpression</li>
+<li>NSString</li>
+<li>NullEncodable</li>
+<li>NumericRule</li>
+<li>NumericValidationErrorKind</li>
+<li>OpenISO8601DateFormatter</li>
 <li>OptionSet</li>
 <li>Optional</li>
+<li>ParameterEncoding</li>
+<li>Progress</li>
 <li>Protocol</li>
 <li>Range</li>
+<li>RequestBuilder</li>
+<li>RequestBuilderFactory</li>
+<li>RequestTask</li>
 <li>Response</li>
 <li>Self</li>
 <li>Set</li>
 <li>StaticString</li>
 <li>String</li>
+<li>StringRule</li>
+<li>StringValidationErrorKind</li>
+<li>SynchronizedDictionary</li>
+<li>TimeZone</li>
 <li>Type</li>
 <li>UInt</li>
 <li>UInt16</li>
@@ -159,7 +206,26 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>UInt64</li>
 <li>UInt8</li>
 <li>URL</li>
+<li>URLAuthenticationChallenge</li>
+<li>URLComponents</li>
+<li>URLCredential</li>
+<li>URLQueryItem</li>
+<li>URLRequest</li>
+<li>URLResponse</li>
+<li>URLSession</li>
+<li>URLSessionConfiguration</li>
+<li>URLSessionDataTask</li>
+<li>URLSessionDataTaskProtocol</li>
+<li>URLSessionDecodableRequestBuilder</li>
+<li>URLSessionProtocol</li>
+<li>URLSessionRequestBuilder</li>
+<li>URLSessionRequestBuilderFactory</li>
+<li>URLSessionTask</li>
+<li>URLSessionTaskDelegate</li>
 <li>Unicode</li>
+<li>UnknownCaseCheckable</li>
+<li>ValidationError</li>
+<li>Validator</li>
 <li>Void</li>
 <li>_</li>
 <li>as</li>
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift5ClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift5ClientCodegen.java
index 7d2a1d9d5154..f7b9eb82c3e0 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift5ClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift5ClientCodegen.java
@@ -213,8 +213,22 @@ public Swift5ClientCodegen() {
 
         reservedWords = new HashSet<>(
                 Arrays.asList(
-                        // name used by swift client
+                        // Types declared by the generated code itself (support files and
+                        // per-library implementations). A model with one of these names
+                        // would be an invalid redeclaration of the client's own type.
                         "ErrorResponse", "Response",
+                        "APIHelper", "AlamofireDecodableRequestBuilder", "AlamofireRequestBuilder",
+                        "AlamofireRequestBuilderFactory", "AnyResponseSerializer", "ArrayRule",
+                        "ArrayValidationErrorKind", "CaseIterableDefaultsLast", "CodableHelper",
+                        "Configuration", "DecodableRequestBuilderError", "DownloadException",
+                        "HTTPMethod", "JSONDataEncoding", "JSONEncodable", "JSONEncodingHelper",
+                        "NullEncodable", "NumericRule", "NumericValidationErrorKind",
+                        "OpenISO8601DateFormatter", "ParameterEncoding", "RequestBuilder",
+                        "RequestBuilderFactory", "RequestTask", "StringRule",
+                        "StringValidationErrorKind", "SynchronizedDictionary", "UnknownCaseCheckable",
+                        "URLSessionDataTaskProtocol", "URLSessionDecodableRequestBuilder",
+                        "URLSessionProtocol", "URLSessionRequestBuilder",
+                        "URLSessionRequestBuilderFactory", "ValidationError", "Validator",
 
                         // Swift keywords. This list is taken from here:
                         // https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/LexicalStructure.html#//apple_ref/doc/uid/TP40014097-CH30-ID410
@@ -251,8 +265,20 @@ public Swift5ClientCodegen() {
                         // Collections
                         "Array", "Dictionary", "Set", "OptionSet", "CountableRange", "CountableClosedRange",
 
-                        // The following are commonly-used Foundation types
+                        // The following are commonly-used Foundation (and stdlib) types that
+                        // the generated support files reference unqualified: a model with one
+                        // of these names would shadow the real type inside the generated
+                        // module and break the client's own code.
                         "URL", "Data", "Codable", "Encodable", "Decodable",
+                        "AnyHashable", "Calendar", "DateFormatter", "DispatchQueue", "FileManager",
+                        "HTTPURLResponse", "JSONDecoder", "JSONEncoder",
+                        "KeyedDecodingContainerProtocol", "KeyedEncodingContainerProtocol",
+                        "Locale", "NSCoder", "NSDecimalNumber", "NSNumber", "NSObject",
+                        "NSRecursiveLock", "NSRegularExpression", "NSString", "Progress",
+                        "TimeZone", "URLAuthenticationChallenge", "URLComponents", "URLCredential",
+                        "URLQueryItem", "URLRequest", "URLResponse", "URLSession",
+                        "URLSessionConfiguration", "URLSessionDataTask", "URLSessionTask",
+                        "URLSessionTaskDelegate",
 
                         // The following are other words we want to reserve
                         "Void", "AnyObject", "Class", "dynamicType", "COLUMN", "FILE", "FUNCTION", "LINE"
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/swift5/Swift5ClientCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/swift5/Swift5ClientCodegenTest.java
index ec64a91269d1..8f965c076159 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/swift5/Swift5ClientCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/swift5/Swift5ClientCodegenTest.java
@@ -163,6 +163,31 @@ public void dateWithoutTimeTest() {
         Assert.assertEquals(op.bodyParam.dataType, "OpenAPIDateWithoutTime");
     }
 
+    @Test(description = "model names colliding with types declared by the generated client are renamed", enabled = true)
+    public void reservedTypeNamesDeclaredByClientTest() {
+        final DefaultCodegen codegen = new Swift5ClientCodegen();
+
+        // Names declared by the generated support files (Validation.swift, Models.swift, ...):
+        // a model with such a name would be an invalid redeclaration of the client's own type.
+        Assert.assertEquals(codegen.toModelName("ValidationError"), "ModelValidationError");
+        Assert.assertEquals(codegen.toModelName("Validator"), "ModelValidator");
+        Assert.assertEquals(codegen.toModelName("Configuration"), "ModelConfiguration");
+        Assert.assertEquals(codegen.toModelName("RequestBuilder"), "ModelRequestBuilder");
+    }
+
+    @Test(description = "model names shadowing Foundation types used by the generated client are renamed", enabled = true)
+    public void reservedFoundationTypeNamesTest() {
+        final DefaultCodegen codegen = new Swift5ClientCodegen();
+
+        // Foundation types the generated support files reference unqualified
+        // (e.g. OpenISO8601DateFormatter.swift assigns `formatter.locale = Locale(...)`):
+        // a model with such a name would shadow the Foundation type inside the module.
+        Assert.assertEquals(codegen.toModelName("Locale"), "ModelLocale");
+        Assert.assertEquals(codegen.toModelName("DateFormatter"), "ModelDateFormatter");
+        Assert.assertEquals(codegen.toModelName("TimeZone"), "ModelTimeZone");
+        Assert.assertEquals(codegen.toModelName("URLSession"), "ModelURLSession");
+    }
+
     @Test(description = "type from languageSpecificPrimitives should not be prefixed", enabled = true)
     public void prefixExceptionTest() {
         final DefaultCodegen codegen = new Swift5ClientCodegen();