diff --git a/discovery/discovery_test.go b/discovery/discovery_test.go
index f597c837..aebc6f5b 100644
--- a/discovery/discovery_test.go
+++ b/discovery/discovery_test.go
@@ -46,3 +46,28 @@ func TestParseDocument(t *testing.T) {
 		t.Errorf("unexpected value for Title: %s (expected %s)", d.Title, title)
 	}
 }
+
+func TestParseDocument_Empty(t *testing.T) {
+	for _, test := range []struct {
+		name string
+		data []byte
+	}{
+		{"nil", nil},
+		{"zero_bytes", []byte{}},
+		{"whitespace", []byte("   ")},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			d, err := ParseDocument(test.data)
+
+			t.Log(err)
+			if err == nil {
+				t.Error("expected error")
+			} else if want, got := "document has no content", err.Error(); want != got {
+				t.Errorf("unexpected error: %q (expected %q)", got, want)
+			}
+			if d != nil {
+				t.Error("expected document to be nil")
+			}
+		})
+	}
+}
diff --git a/discovery/document.go b/discovery/document.go
index 13316d1b..2745d94c 100644
--- a/discovery/document.go
+++ b/discovery/document.go
@@ -15,6 +15,8 @@
 package discovery_v1
 
 import (
+	"errors"
+
 	"github.com/google/gnostic/compiler"
 )
 
@@ -29,6 +31,11 @@ func ParseDocument(b []byte) (*Document, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	if len(info.Content) < 1 {
+		return nil, errors.New("document has no content")
+	}
+
 	root := info.Content[0]
 	return NewDocument(root, compiler.NewContext("$root", root, nil))
 }
diff --git a/openapiv2/document.go b/openapiv2/document.go
index 0021ae87..98d67135 100644
--- a/openapiv2/document.go
+++ b/openapiv2/document.go
@@ -15,6 +15,8 @@
 package openapi_v2
 
 import (
+	"errors"
+
 	"gopkg.in/yaml.v3"
 
 	"github.com/google/gnostic/compiler"
@@ -26,6 +28,11 @@ func ParseDocument(b []byte) (*Document, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	if len(info.Content) < 1 {
+		return nil, errors.New("document has no content")
+	}
+
 	root := info.Content[0]
 	return NewDocument(root, compiler.NewContextWithExtensions("$root", root, nil, nil))
 }
diff --git a/openapiv2/document_test.go b/openapiv2/document_test.go
new file mode 100644
index 00000000..1a26a8ec
--- /dev/null
+++ b/openapiv2/document_test.go
@@ -0,0 +1,42 @@
+// Copyright 2023 Google LLC. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package openapi_v2
+
+import "testing"
+
+func TestParseDocument_Empty(t *testing.T) {
+	for _, test := range []struct {
+		name string
+		data []byte
+	}{
+		{"nil", nil},
+		{"zero_bytes", []byte{}},
+		{"whitespace", []byte("   ")},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			d, err := ParseDocument(test.data)
+
+			t.Log(err)
+			if err == nil {
+				t.Error("expected error")
+			} else if want, got := "document has no content", err.Error(); want != got {
+				t.Errorf("unexpected error: %q (expected %q)", got, want)
+			}
+			if d != nil {
+				t.Error("expected document to be nil")
+			}
+		})
+	}
+}
diff --git a/openapiv3/document.go b/openapiv3/document.go
index ef10d1d9..26b2d948 100644
--- a/openapiv3/document.go
+++ b/openapiv3/document.go
@@ -15,6 +15,8 @@
 package openapi_v3
 
 import (
+	"errors"
+
 	"gopkg.in/yaml.v3"
 
 	"github.com/google/gnostic/compiler"
@@ -26,6 +28,11 @@ func ParseDocument(b []byte) (*Document, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	if len(info.Content) < 1 {
+		return nil, errors.New("document has no content")
+	}
+
 	root := info.Content[0]
 	return NewDocument(root, compiler.NewContextWithExtensions("$root", root, nil, nil))
 }
diff --git a/openapiv3/openapiv3_test.go b/openapiv3/openapiv3_test.go
index 4117c48e..621cab51 100644
--- a/openapiv3/openapiv3_test.go
+++ b/openapiv3/openapiv3_test.go
@@ -36,3 +36,28 @@ func TestParseDocument(t *testing.T) {
 		t.Errorf("unexpected value for Title: %s (expected %s)", d.Info.Title, title)
 	}
 }
+
+func TestParseDocument_Empty(t *testing.T) {
+	for _, test := range []struct {
+		name string
+		data []byte
+	}{
+		{"nil", nil},
+		{"zero_bytes", []byte{}},
+		{"whitespace", []byte("   ")},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			d, err := ParseDocument(test.data)
+
+			t.Log(err)
+			if err == nil {
+				t.Error("expected error")
+			} else if want, got := "document has no content", err.Error(); want != got {
+				t.Errorf("unexpected error: %q (expected %q)", got, want)
+			}
+			if d != nil {
+				t.Error("expected document to be nil")
+			}
+		})
+	}
+}