diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
index d588e42b0995..188436a75eb5 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
@@ -601,6 +601,7 @@ public String toOperationId(String operationId) {
     public ModelsMap postProcessModels(ModelsMap objs) {
         for (ModelMap mo : objs.getModels()) {
             CodegenModel cm = mo.getModel();
+            boolean needsExtractSimpleType = false;
             for (CodegenProperty var : cm.vars) {
                 // check to see if base name is an empty string
                 if ("".equals(var.baseName)) {
@@ -608,10 +609,17 @@ public ModelsMap postProcessModels(ModelsMap objs) {
                     var.baseName = "empty_string";
                 }
 
+                if (!var.isPrimitiveType) {
+                    needsExtractSimpleType = true;
+                }
+
                 // create extension x-r-doc-type to store the data type in r doc format
                 var.vendorExtensions.put("x-r-doc-type", constructRdocType(var));
             }
 
+            // create extension x-r-has-non-primitive-field to indicate whether generated models need special handling for complex types
+            cm.vendorExtensions.put("x-r-has-non-primitive-field", needsExtractSimpleType);
+
             // apply the same fix, enhancement for allVars
             for (CodegenProperty var : cm.allVars) {
                 // check to see if base name is an empty string
diff --git a/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache b/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
index 0da6607925aa..ed5873bd9305 100644
--- a/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
+++ b/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
@@ -242,7 +242,7 @@
           self$`{{name}}`
           {{/isPrimitiveType}}
           {{^isPrimitiveType}}
-          lapply(self$`{{name}}`, function(x) x$toSimpleType())
+          self$extractSimpleType(self$`{{name}}`)
           {{/isPrimitiveType}}
           {{/isArray}}
           {{#isMap}}
@@ -250,7 +250,7 @@
           self$`{{name}}`
           {{/isPrimitiveType}}
           {{^isPrimitiveType}}
-          lapply(self$`{{name}}`, function(x) x$toSimpleType())
+          self$extractSimpleType(self$`{{name}}`)
           {{/isPrimitiveType}}
           {{/isMap}}
           {{/isContainer}}
@@ -259,7 +259,7 @@
           self$`{{name}}`
           {{/isPrimitiveType}}
           {{^isPrimitiveType}}
-          self$`{{name}}`$toSimpleType()
+          self$extractSimpleType(self$`{{name}}`)
           {{/isPrimitiveType}}
           {{/isContainer}}
       }
@@ -272,6 +272,31 @@
       {{/isAdditionalPropertiesTrue}}
       return({{classname}}Object)
     },
+    {{#vendorExtensions.x-r-has-non-primitive-field}}
+
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+    {{/vendorExtensions.x-r-has-non-primitive-field}}
 
     #' @description
     #' Deserialize JSON string into an instance of {{{classname}}}
diff --git a/samples/client/echo_api/r/R/default_value.R b/samples/client/echo_api/r/R/default_value.R
index 2a3a83f32655..e6a089514fc0 100644
--- a/samples/client/echo_api/r/R/default_value.R
+++ b/samples/client/echo_api/r/R/default_value.R
@@ -119,7 +119,7 @@ DefaultValue <- R6::R6Class(
       DefaultValueObject <- list()
       if (!is.null(self$`array_string_enum_ref_default`)) {
         DefaultValueObject[["array_string_enum_ref_default"]] <-
-          lapply(self$`array_string_enum_ref_default`, function(x) x$toSimpleType())
+          self$extractSimpleType(self$`array_string_enum_ref_default`)
       }
       if (!is.null(self$`array_string_enum_default`)) {
         DefaultValueObject[["array_string_enum_default"]] <-
@@ -152,6 +152,29 @@ DefaultValue <- R6::R6Class(
       return(DefaultValueObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of DefaultValue
     #'
diff --git a/samples/client/echo_api/r/R/pet.R b/samples/client/echo_api/r/R/pet.R
index 6f59d7ea1f6c..b4cae7506eec 100644
--- a/samples/client/echo_api/r/R/pet.R
+++ b/samples/client/echo_api/r/R/pet.R
@@ -115,7 +115,7 @@ Pet <- R6::R6Class(
       }
       if (!is.null(self$`category`)) {
         PetObject[["category"]] <-
-          self$`category`$toSimpleType()
+          self$extractSimpleType(self$`category`)
       }
       if (!is.null(self$`photoUrls`)) {
         PetObject[["photoUrls"]] <-
@@ -123,7 +123,7 @@ Pet <- R6::R6Class(
       }
       if (!is.null(self$`tags`)) {
         PetObject[["tags"]] <-
-          lapply(self$`tags`, function(x) x$toSimpleType())
+          self$extractSimpleType(self$`tags`)
       }
       if (!is.null(self$`status`)) {
         PetObject[["status"]] <-
@@ -132,6 +132,29 @@ Pet <- R6::R6Class(
       return(PetObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of Pet
     #'
diff --git a/samples/client/petstore/R-httr2-wrapper/R/nested_one_of.R b/samples/client/petstore/R-httr2-wrapper/R/nested_one_of.R
index 31dcc2f10d01..fe396f11faa4 100644
--- a/samples/client/petstore/R-httr2-wrapper/R/nested_one_of.R
+++ b/samples/client/petstore/R-httr2-wrapper/R/nested_one_of.R
@@ -84,7 +84,7 @@ NestedOneOf <- R6::R6Class(
       }
       if (!is.null(self$`nested_pig`)) {
         NestedOneOfObject[["nested_pig"]] <-
-          self$`nested_pig`$toSimpleType()
+          self$extractSimpleType(self$`nested_pig`)
       }
       for (key in names(self$additional_properties)) {
         NestedOneOfObject[[key]] <- self$additional_properties[[key]]
@@ -93,6 +93,29 @@ NestedOneOf <- R6::R6Class(
       return(NestedOneOfObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of NestedOneOf
     #'
diff --git a/samples/client/petstore/R-httr2-wrapper/R/pet.R b/samples/client/petstore/R-httr2-wrapper/R/pet.R
index 27db68d8fdbd..37d2db91adb7 100644
--- a/samples/client/petstore/R-httr2-wrapper/R/pet.R
+++ b/samples/client/petstore/R-httr2-wrapper/R/pet.R
@@ -121,7 +121,7 @@ Pet <- R6::R6Class(
       }
       if (!is.null(self$`category`)) {
         PetObject[["category"]] <-
-          self$`category`$toSimpleType()
+          self$extractSimpleType(self$`category`)
       }
       if (!is.null(self$`name`)) {
         PetObject[["name"]] <-
@@ -133,7 +133,7 @@ Pet <- R6::R6Class(
       }
       if (!is.null(self$`tags`)) {
         PetObject[["tags"]] <-
-          lapply(self$`tags`, function(x) x$toSimpleType())
+          self$extractSimpleType(self$`tags`)
       }
       if (!is.null(self$`status`)) {
         PetObject[["status"]] <-
@@ -146,6 +146,29 @@ Pet <- R6::R6Class(
       return(PetObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of Pet
     #'
diff --git a/samples/client/petstore/R-httr2-wrapper/R/update_pet_request.R b/samples/client/petstore/R-httr2-wrapper/R/update_pet_request.R
index 3559d3c4d838..7a4fb1112f75 100644
--- a/samples/client/petstore/R-httr2-wrapper/R/update_pet_request.R
+++ b/samples/client/petstore/R-httr2-wrapper/R/update_pet_request.R
@@ -77,7 +77,7 @@ UpdatePetRequest <- R6::R6Class(
       UpdatePetRequestObject <- list()
       if (!is.null(self$`jsonData`)) {
         UpdatePetRequestObject[["jsonData"]] <-
-          self$`jsonData`$toSimpleType()
+          self$extractSimpleType(self$`jsonData`)
       }
       if (!is.null(self$`binaryDataN2Information`)) {
         UpdatePetRequestObject[["binaryDataN2Information"]] <-
@@ -90,6 +90,29 @@ UpdatePetRequest <- R6::R6Class(
       return(UpdatePetRequestObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of UpdatePetRequest
     #'
diff --git a/samples/client/petstore/R-httr2/R/nested_one_of.R b/samples/client/petstore/R-httr2/R/nested_one_of.R
index d0ef1f9b67a5..dc43a39e5f41 100644
--- a/samples/client/petstore/R-httr2/R/nested_one_of.R
+++ b/samples/client/petstore/R-httr2/R/nested_one_of.R
@@ -74,11 +74,34 @@ NestedOneOf <- R6::R6Class(
       }
       if (!is.null(self$`nested_pig`)) {
         NestedOneOfObject[["nested_pig"]] <-
-          self$`nested_pig`$toSimpleType()
+          self$extractSimpleType(self$`nested_pig`)
       }
       return(NestedOneOfObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of NestedOneOf
     #'
diff --git a/samples/client/petstore/R-httr2/R/pet.R b/samples/client/petstore/R-httr2/R/pet.R
index c3d0bc32fd61..93e6b64c3e7b 100644
--- a/samples/client/petstore/R-httr2/R/pet.R
+++ b/samples/client/petstore/R-httr2/R/pet.R
@@ -111,7 +111,7 @@ Pet <- R6::R6Class(
       }
       if (!is.null(self$`category`)) {
         PetObject[["category"]] <-
-          self$`category`$toSimpleType()
+          self$extractSimpleType(self$`category`)
       }
       if (!is.null(self$`name`)) {
         PetObject[["name"]] <-
@@ -123,7 +123,7 @@ Pet <- R6::R6Class(
       }
       if (!is.null(self$`tags`)) {
         PetObject[["tags"]] <-
-          lapply(self$`tags`, function(x) x$toSimpleType())
+          self$extractSimpleType(self$`tags`)
       }
       if (!is.null(self$`status`)) {
         PetObject[["status"]] <-
@@ -132,6 +132,29 @@ Pet <- R6::R6Class(
       return(PetObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of Pet
     #'
diff --git a/samples/client/petstore/R-httr2/R/update_pet_request.R b/samples/client/petstore/R-httr2/R/update_pet_request.R
index e42c9a114546..dc2ede0a8e16 100644
--- a/samples/client/petstore/R-httr2/R/update_pet_request.R
+++ b/samples/client/petstore/R-httr2/R/update_pet_request.R
@@ -67,7 +67,7 @@ UpdatePetRequest <- R6::R6Class(
       UpdatePetRequestObject <- list()
       if (!is.null(self$`jsonData`)) {
         UpdatePetRequestObject[["jsonData"]] <-
-          self$`jsonData`$toSimpleType()
+          self$extractSimpleType(self$`jsonData`)
       }
       if (!is.null(self$`binaryDataN2Information`)) {
         UpdatePetRequestObject[["binaryDataN2Information"]] <-
@@ -76,6 +76,29 @@ UpdatePetRequest <- R6::R6Class(
       return(UpdatePetRequestObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of UpdatePetRequest
     #'
diff --git a/samples/client/petstore/R/R/nested_one_of.R b/samples/client/petstore/R/R/nested_one_of.R
index 31dcc2f10d01..fe396f11faa4 100644
--- a/samples/client/petstore/R/R/nested_one_of.R
+++ b/samples/client/petstore/R/R/nested_one_of.R
@@ -84,7 +84,7 @@ NestedOneOf <- R6::R6Class(
       }
       if (!is.null(self$`nested_pig`)) {
         NestedOneOfObject[["nested_pig"]] <-
-          self$`nested_pig`$toSimpleType()
+          self$extractSimpleType(self$`nested_pig`)
       }
       for (key in names(self$additional_properties)) {
         NestedOneOfObject[[key]] <- self$additional_properties[[key]]
@@ -93,6 +93,29 @@ NestedOneOf <- R6::R6Class(
       return(NestedOneOfObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of NestedOneOf
     #'
diff --git a/samples/client/petstore/R/R/pet.R b/samples/client/petstore/R/R/pet.R
index 27db68d8fdbd..37d2db91adb7 100644
--- a/samples/client/petstore/R/R/pet.R
+++ b/samples/client/petstore/R/R/pet.R
@@ -121,7 +121,7 @@ Pet <- R6::R6Class(
       }
       if (!is.null(self$`category`)) {
         PetObject[["category"]] <-
-          self$`category`$toSimpleType()
+          self$extractSimpleType(self$`category`)
       }
       if (!is.null(self$`name`)) {
         PetObject[["name"]] <-
@@ -133,7 +133,7 @@ Pet <- R6::R6Class(
       }
       if (!is.null(self$`tags`)) {
         PetObject[["tags"]] <-
-          lapply(self$`tags`, function(x) x$toSimpleType())
+          self$extractSimpleType(self$`tags`)
       }
       if (!is.null(self$`status`)) {
         PetObject[["status"]] <-
@@ -146,6 +146,29 @@ Pet <- R6::R6Class(
       return(PetObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of Pet
     #'
diff --git a/samples/client/petstore/R/R/update_pet_request.R b/samples/client/petstore/R/R/update_pet_request.R
index 3559d3c4d838..7a4fb1112f75 100644
--- a/samples/client/petstore/R/R/update_pet_request.R
+++ b/samples/client/petstore/R/R/update_pet_request.R
@@ -77,7 +77,7 @@ UpdatePetRequest <- R6::R6Class(
       UpdatePetRequestObject <- list()
       if (!is.null(self$`jsonData`)) {
         UpdatePetRequestObject[["jsonData"]] <-
-          self$`jsonData`$toSimpleType()
+          self$extractSimpleType(self$`jsonData`)
       }
       if (!is.null(self$`binaryDataN2Information`)) {
         UpdatePetRequestObject[["binaryDataN2Information"]] <-
@@ -90,6 +90,29 @@ UpdatePetRequest <- R6::R6Class(
       return(UpdatePetRequestObject)
     },
 
+    extractSimpleType = function(x) {
+      if (R6::is.R6(x)) {
+        return(x$toSimpleType())
+      } else if (!self$hasNestedR6(x)) {
+        return(x)
+      }
+      lapply(x, self$extractSimpleType)
+    },
+
+    hasNestedR6 = function(x) {
+      if (R6::is.R6(x)) {
+        return(TRUE)
+      }
+      if (is.list(x)) {
+        for (item in x) {
+          if (self$hasNestedR6(item)) {
+            return(TRUE)
+          }
+        }
+      }
+      FALSE
+    },
+
     #' @description
     #' Deserialize JSON string into an instance of UpdatePetRequest
     #'