diff --git a/.changeset/cuddly-rules-behave.md b/.changeset/cuddly-rules-behave.md
new file mode 100644
index 00000000..65bf91c8
--- /dev/null
+++ b/.changeset/cuddly-rules-behave.md
@@ -0,0 +1,5 @@
+---
+'react-native-app-auth': minor
+---
+
+#965 remove duplicate state key
diff --git a/ios/RNAppAuth.m b/ios/RNAppAuth.m
index eb11aa55..6b0e387a 100644
--- a/ios/RNAppAuth.m
+++ b/ios/RNAppAuth.m
@@ -338,6 +338,9 @@ - (void)authorizeWithConfiguration: (OIDServiceConfiguration *) configuration
     NSString *codeVerifier = usePKCE ? [[self class] generateCodeVerifier] : nil;
     NSString *codeChallenge = usePKCE ? [[self class] codeChallengeS256ForVerifier:codeVerifier] : nil;
     NSString *nonce =  useNonce ? additionalParameters[@"nonce"]? additionalParameters[@"nonce"]:  [[self class] generateState] : nil ;
+    
+    NSMutableDictionary* mutableDict = [additionalParameters mutableCopy];
+    [mutableDict removeObjectForKey:@"state"];
 
     // builds authentication request
     OIDAuthorizationRequest *request =
@@ -353,7 +356,7 @@ - (void)authorizeWithConfiguration: (OIDServiceConfiguration *) configuration
                                               codeVerifier:codeVerifier
                                              codeChallenge:codeChallenge
                                       codeChallengeMethod: usePKCE ? OIDOAuthorizationRequestCodeChallengeMethodS256 : nil
-                                      additionalParameters:additionalParameters];
+                                      additionalParameters:[mutableDict copy]];
 
     // performs authentication request
     id<UIApplicationDelegate, RNAppAuthAuthorizationFlowManager> appDelegate = (id<UIApplicationDelegate, RNAppAuthAuthorizationFlowManager>)[UIApplication sharedApplication].delegate;