diff --git a/README.md b/README.md
index fb22b3a..86e4ee2 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,8 @@ running Terraform.
 - `--disallow-additional-properties`: Set additionalProperties to false in the root object and nested objects
   (see [JSON Schema definition](https://json-schema.org/understanding-json-schema/reference/object#additionalproperties)).
 
+- `--nullable-all`: Change the default value for `nullable` in a Variable block to 'true'. This is to make the behaviour more closely reflect Terraform's own validation. See 'Nullable Variables' below.
+
 - `--overwrite`: Allow overwriting an existing file at the output location.
 
 - `--debug`: Print debug logs for variable retrieval and errors related to custom validation rules.
@@ -295,7 +297,78 @@ If `nullable` is true in the `variable` block, then the JSON Schema will be modi
 },
 ```
 
-This is actually a slight behaviour change from the validator used by terraform. If `nullable` is unset, then terraform treats them as `nullable` by default. I chose not to implement that behaviour here and instead am making the Terraform module author specify `nullable = true`. This is because otherwise schema definitions for simple programs would have to become a lot more verbose just to handle this case.
+This is actually a slight behaviour change from the validator used by terraform. If `nullable` is unset, then terraform treats them as `nullable` by default. I chose not to implement that default behaviour here and instead am making the Terraform module author specify `nullable = true`. This is because otherwise schema definitions for simple programs would have to become a lot more verbose just to handle this case.
+
+For behaviour more consistent with Terraform, the flag `--nullable-all` can be used to reset the default value for nullable to be true. Note: this rule only applies to variables which have not explicitly set the value of nullable themselves. See [Terraform documentation on nullable](https://developer.hashicorp.com/terraform/language/values/variables#disallowing-null-input-values
+).
+
+As an example, here is a Terraform configuration file which does not specify `nullable`:
+
+```hcl
+variable "name" {
+    type = string
+    nullable = false
+}
+
+variable "age" {
+    type = number
+    default = 10
+}
+```
+
+Without `--nullable-all`, this would result in the following JSON Schema file: 
+
+```json
+{
+    "additionalProperties": true,
+    "properties": {
+        "age": {
+            "default": 10,
+            "type": "number"
+        },
+        "name": {
+            "type": "string"
+        }
+    },
+    "required": [
+        "age",
+        "name"
+    ]
+}
+```
+
+And if `--nullable-all` is set to true, then the 'default' value for nullable will be true, so the schema will change to reflect this:
+
+```json
+{
+    "additionalProperties": true,
+    "properties": {
+        "age": {
+            "anyOf": [
+                {
+                    "title": "null",
+                    "type": "null"
+                },
+                {
+                    "title": "number",
+                    "type": "number"
+                }
+            ],
+            "default": 10,
+            "title": "age: Select a type"
+        },
+        "name": {
+            "type": "string"
+        }
+    },
+    "required": [
+        "age",
+        "name"
+    ]
+}
+```
+
+`name` is not affected here since it has `nullable = false` in its HCL definition.
 
 ### Default Handling
 
diff --git a/cmd/cmd.go b/cmd/cmd.go
index 7a0d5d8..ff95f41 100644
--- a/cmd/cmd.go
+++ b/cmd/cmd.go
@@ -19,6 +19,7 @@ var (
 	allowEmpty                   bool
 	requireAll                   bool
 	outputStdOut                 bool
+	nullableAll                  bool
 	inputPath                    string
 	outputPath                   string
 	debugOut                     bool
@@ -88,6 +89,10 @@ func init() {
 			"validation rules. Does not work with --stdout",
 	)
 
+	rootCmd.Flags().BoolVar(&nullableAll, "nullable-all", false,
+		"make all variables nullable unless nullable set to false explicitly, to make behavior consistent with Terraform",
+	)
+
 	rootCmd.SetFlagErrorFunc(func(cmd *cobra.Command, err error) error {
 		_ = rootCmd.Usage()
 
@@ -160,6 +165,7 @@ func runCommand(cmd *cobra.Command, args []string) error {
 		AllowEmpty:                allowEmpty,
 		DebugOut:                  debugOut && !outputStdOut,
 		SuppressLogging:           outputStdOut,
+		NullableAll:               nullableAll,
 	})
 	if err != nil {
 		return fmt.Errorf("error creating schema: %w", err)
diff --git a/pkg/jsonschema/json-schema.go b/pkg/jsonschema/json-schema.go
index c718b78..77ba5c6 100644
--- a/pkg/jsonschema/json-schema.go
+++ b/pkg/jsonschema/json-schema.go
@@ -16,6 +16,7 @@ type CreateSchemaOptions struct {
 	AllowEmpty                bool
 	DebugOut                  bool
 	SuppressLogging           bool
+	NullableAll               bool
 }
 
 func CreateSchema(path string, options CreateSchemaOptions) (map[string]any, error) {
@@ -69,8 +70,14 @@ func createNode(name string, v model.TranslatedVariable, options CreateSchemaOpt
 		return nil, fmt.Errorf("getting type constraint for %q: %w", name, err)
 	}
 
-	nullableIsTrue := v.Variable.Nullable != nil && *v.Variable.Nullable
-	node, err := getNodeFromType(name, tc, nullableIsTrue, options)
+	// The default value for nullable is the value of NullableAll. For the purpose of keeping the JSON Schema relatively
+	// clean, this is normally set to false. Setting the default value to true is consistent with Terraform behavior.
+	nullableTranslatedValue := options.NullableAll
+	if v.Variable.Nullable != nil {
+		nullableTranslatedValue = *v.Variable.Nullable
+	}
+
+	node, err := getNodeFromType(name, tc, nullableTranslatedValue, options)
 	if err != nil {
 		return nil, fmt.Errorf("%q: %w", name, err)
 	}
diff --git a/pkg/jsonschema/json-schema_test.go b/pkg/jsonschema/json-schema_test.go
index 0684777..2f7b00e 100644
--- a/pkg/jsonschema/json-schema_test.go
+++ b/pkg/jsonschema/json-schema_test.go
@@ -36,6 +36,7 @@ func TestCreateSchema(t *testing.T) {
 				RequireAll:                false,
 				AllowAdditionalProperties: true,
 				AllowEmpty:                true,
+				NullableAll:               false,
 			})
 			require.NoError(t, err)