diff --git a/openapi3/issue652_test.go b/openapi3/issue652_test.go
new file mode 100644
index 000000000..f36e92005
--- /dev/null
+++ b/openapi3/issue652_test.go
@@ -0,0 +1,29 @@
+package openapi3_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/getkin/kin-openapi/openapi3"
+)
+
+func TestIssue652(t *testing.T) {
+	loader := openapi3.NewLoader()
+	loader.IsExternalRefsAllowed = true
+
+	// Test checks that no slice bounds out of range error occurs while loading
+	// from file that contains reference to file in the parent directory.
+	require.NotPanics(t, func() {
+		const schemaName = "ReferenceToParentDirectory"
+
+		spec, err := loader.LoadFromFile("testdata/issue652/nested/schema.yml")
+		require.NoError(t, err)
+		require.Contains(t, spec.Components.Schemas, schemaName)
+
+		schema := spec.Components.Schemas[schemaName]
+		assert.Equal(t, schema.Ref, "../definitions.yml#/components/schemas/TestSchema")
+		assert.Equal(t, schema.Value.Type, "string")
+	})
+}
diff --git a/openapi3/loader.go b/openapi3/loader.go
index 1ab693b0f..2bb9999ee 100644
--- a/openapi3/loader.go
+++ b/openapi3/loader.go
@@ -742,7 +742,10 @@ func (loader *Loader) resolveSchemaRef(doc *T, component *SchemaRef, documentPat
 				return err
 			}
 			component.Value = resolved.Value
-			foundPath := loader.getResolvedRefPath(ref, &resolved, documentPath, componentPath)
+			foundPath, rerr := loader.getResolvedRefPath(ref, &resolved, documentPath, componentPath)
+			if rerr != nil {
+				return fmt.Errorf("failed to resolve file from reference %q: %w", ref, rerr)
+			}
 			documentPath = loader.documentPathForRecursiveRef(documentPath, foundPath)
 		}
 	}
@@ -790,23 +793,28 @@ func (loader *Loader) resolveSchemaRef(doc *T, component *SchemaRef, documentPat
 	return nil
 }
 
-func (loader *Loader) getResolvedRefPath(ref string, resolved *SchemaRef, cur, found *url.URL) string {
+func (loader *Loader) getResolvedRefPath(ref string, resolved *SchemaRef, cur, found *url.URL) (string, error) {
 	if referencedFilename := strings.Split(ref, "#")[0]; referencedFilename == "" {
 		if cur != nil {
 			if loader.rootDir != "" && strings.HasPrefix(cur.Path, loader.rootDir) {
-				return cur.Path[len(loader.rootDir)+1:]
+				return cur.Path[len(loader.rootDir)+1:], nil
 			}
 
-			return path.Base(cur.Path)
+			return path.Base(cur.Path), nil
 		}
-		return ""
+		return "", nil
 	}
 	// ref. to external file
 	if resolved.Ref != "" {
-		return resolved.Ref
+		return resolved.Ref, nil
 	}
+
+	if loader.rootDir == "" {
+		return found.Path, nil
+	}
+
 	// found dest spec. file
-	return path.Dir(found.Path)[len(loader.rootDir):]
+	return filepath.Rel(loader.rootDir, found.Path)
 }
 
 func (loader *Loader) resolveSecuritySchemeRef(doc *T, component *SecuritySchemeRef, documentPath *url.URL) (err error) {
diff --git a/openapi3/testdata/issue652/definitions.yml b/openapi3/testdata/issue652/definitions.yml
new file mode 100644
index 000000000..98ef69254
--- /dev/null
+++ b/openapi3/testdata/issue652/definitions.yml
@@ -0,0 +1,4 @@
+components:
+    schemas:
+        TestSchema:
+            type: string
diff --git a/openapi3/testdata/issue652/nested/schema.yml b/openapi3/testdata/issue652/nested/schema.yml
new file mode 100644
index 000000000..ef321a101
--- /dev/null
+++ b/openapi3/testdata/issue652/nested/schema.yml
@@ -0,0 +1,4 @@
+components:
+    schemas:
+        ReferenceToParentDirectory:
+            $ref: "../definitions.yml#/components/schemas/TestSchema"