diff --git a/butane/config/common/common.go b/butane/config/common/common.go
index f760bfaa7..55797f61b 100644
--- a/butane/config/common/common.go
+++ b/butane/config/common/common.go
@@ -22,6 +22,7 @@ type TranslateOptions struct {
 
 type TranslateBytesOptions struct {
 	TranslateOptions
-	Pretty bool
-	Raw    bool // encode only the Ignition config, not any wrapper
+	Pretty                bool
+	Raw                   bool // encode only the Ignition config, not any wrapper
+	YAMLDocumentSeparator bool // prepend YAML document separator (---) to YAML output
 }
diff --git a/butane/config/openshift/v4_23_exp/translate_test.go b/butane/config/openshift/v4_23_exp/translate_test.go
index 13980a3e2..629ac6e17 100644
--- a/butane/config/openshift/v4_23_exp/translate_test.go
+++ b/butane/config/openshift/v4_23_exp/translate_test.go
@@ -16,6 +16,7 @@ package v4_23_exp
 
 import (
 	"fmt"
+	"strings"
 	"testing"
 
 	baseutil "github.com/coreos/ignition/v2/butane/base/util"
@@ -422,3 +423,34 @@ func TestValidateSupport(t *testing.T) {
 		})
 	}
 }
+
+// TestYAMLDocumentSeparator tests that the YAML document separator is only
+// emitted when requested.
+func TestYAMLDocumentSeparator(t *testing.T) {
+	in := []byte(`variant: openshift
+version: 4.23.0-experimental
+metadata:
+  name: something
+  labels:
+    machineconfiguration.openshift.io/role: worker
+`)
+
+	tests := []struct {
+		separator bool
+		prefix    string
+	}{
+		{false, "# Generated by Butane; do not edit\n"},
+		{true, "---\n# Generated by Butane; do not edit\n"},
+	}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprintf("separator %v", test.separator), func(t *testing.T) {
+			actual, r, err := ToConfigBytes(in, common.TranslateBytesOptions{
+				YAMLDocumentSeparator: test.separator,
+			})
+			assert.NoError(t, err, "translation failed")
+			assert.False(t, r.IsFatal(), "fatal report: %v", r)
+			assert.True(t, strings.HasPrefix(string(actual), test.prefix), "expected prefix %q, got %q", test.prefix, string(actual))
+		})
+	}
+}
diff --git a/butane/config/util/util.go b/butane/config/util/util.go
index fc6de99db..b49e2fa8e 100644
--- a/butane/config/util/util.go
+++ b/butane/config/util/util.go
@@ -161,6 +161,9 @@ func TranslateBytesYAML(input []byte, container interface{}, translateMethod str
 	}
 
 	var yamlCfgBuf bytes.Buffer
+	if options.YAMLDocumentSeparator {
+		yamlCfgBuf.WriteString("---\n")
+	}
 	yamlCfgBuf.WriteString("# Generated by Butane; do not edit\n")
 	encoder := yaml.NewEncoder(&yamlCfgBuf)
 	encoder.SetIndent(2)
diff --git a/butane/internal/main.go b/butane/internal/main.go
index 1d384ff37..98dd97427 100644
--- a/butane/internal/main.go
+++ b/butane/internal/main.go
@@ -61,6 +61,7 @@ func main() {
 	pflag.BoolVarP(&strict, "strict", "s", false, "fail on any warning")
 	pflag.BoolVarP(&options.Pretty, "pretty", "p", false, "output formatted json")
 	pflag.BoolVarP(&options.Raw, "raw", "r", false, "never wrap in a MachineConfig; force Ignition output")
+	pflag.BoolVar(&options.YAMLDocumentSeparator, "yaml-doc-separator", false, "prepend YAML document separator (---) to YAML output")
 	pflag.BoolVar(&rawErrors, "raw-errors", false, "show raw errors, rather than pretty printing them")
 	pflag.StringVar(&colorFlag, "color", "auto", `control color output: "auto", "always", or "never"`)
 	pflag.Lookup("color").NoOptDefVal = "always"
diff --git a/docs/release-notes.md b/docs/release-notes.md
index e4015a63f..1fde37e5d 100644
--- a/docs/release-notes.md
+++ b/docs/release-notes.md
@@ -10,6 +10,9 @@ nav_order: 9
 
 ### Features
 
+- Butane: add `--yaml-doc-separator` to prepend the YAML document separator
+  (`---`) to MachineConfig output
+
 ### Changes
 
 ### Bug fixes