diff --git a/rhel/dockerfile/dockerfile.go b/rhel/dockerfile/dockerfile.go
index d450dc9ca..f47762ea8 100644
--- a/rhel/dockerfile/dockerfile.go
+++ b/rhel/dockerfile/dockerfile.go
@@ -95,12 +95,15 @@ func (p *labelParser) Run() error {
 					return err
 				}
 				for _, kv := range pairs {
-					i := strings.IndexByte(kv, '=')
-					k, _, err := transform.String(p.unquote, kv[:i])
+					idx := strings.IndexByte(kv, '=')
+					if idx == -1 {
+						return fmt.Errorf(`invalid syntax: %+#q`, i.val)
+					}
+					k, _, err := transform.String(p.unquote, kv[:idx])
 					if err != nil {
 						return err
 					}
-					v, _, err := transform.String(transform.Chain(p.unquote, p.vars), kv[i+1:])
+					v, _, err := transform.String(transform.Chain(p.unquote, p.vars), kv[idx+1:])
 					if err != nil {
 						return err
 					}
@@ -127,12 +130,15 @@ func (p *labelParser) Run() error {
 				return err
 			}
 			for _, kv := range pairs {
-				i := strings.IndexByte(kv, '=')
-				k, _, err := transform.String(p.unquote, kv[:i])
+				idx := strings.IndexByte(kv, '=')
+				if idx == -1 {
+					return fmt.Errorf(`invalid syntax: %+#q`, i.val)
+				}
+				k, _, err := transform.String(p.unquote, kv[:idx])
 				if err != nil {
 					return err
 				}
-				v, _, err := transform.String(transform.Chain(p.unquote, p.vars), kv[i+1:])
+				v, _, err := transform.String(transform.Chain(p.unquote, p.vars), kv[idx+1:])
 				if err != nil {
 					return err
 				}
diff --git a/rhel/dockerfile/itemkind_string.go b/rhel/dockerfile/itemkind_string.go
new file mode 100644
index 000000000..bbdaa236a
--- /dev/null
+++ b/rhel/dockerfile/itemkind_string.go
@@ -0,0 +1,29 @@
+// Code generated by "stringer -type itemKind lex.go"; DO NOT EDIT.
+
+package dockerfile
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[itemError-0]
+	_ = x[itemComment-1]
+	_ = x[itemInstruction-2]
+	_ = x[itemLabel-3]
+	_ = x[itemArg-4]
+	_ = x[itemEnv-5]
+	_ = x[itemEOF-6]
+}
+
+const _itemKind_name = "itemErroritemCommentitemInstructionitemLabelitemArgitemEnvitemEOF"
+
+var _itemKind_index = [...]uint8{0, 9, 20, 35, 44, 51, 58, 65}
+
+func (i itemKind) String() string {
+	if i < 0 || i >= itemKind(len(_itemKind_index)-1) {
+		return "itemKind(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _itemKind_name[_itemKind_index[i]:_itemKind_index[i+1]]
+}
diff --git a/rhel/dockerfile/lex.go b/rhel/dockerfile/lex.go
index 2aa41fbf3..b28ff1e94 100644
--- a/rhel/dockerfile/lex.go
+++ b/rhel/dockerfile/lex.go
@@ -58,6 +58,8 @@ type item struct {
 
 type itemKind int
 
+//go:generate stringer -type itemKind $GOFILE
+
 const (
 	itemError itemKind = iota
 	itemComment
@@ -118,13 +120,18 @@ func (l *lexer) consumeWhitespace() (err error) {
 func (l *lexer) collectLine() (err error) {
 	var r rune
 	var sz int
-	var esc bool
+	var esc, inComment, started bool
 Read:
 	for r, sz, err = l.rd.ReadRune(); err == nil; r, sz, err = l.rd.ReadRune() {
 		switch {
+		case inComment && r == '\n':
+			inComment = false
+			started = false
+		case inComment: // Skip
 		case esc && r == '\r': // Lexer hack: why do some things have DOS line endings?
 		case esc && r == '\n':
 			esc = false
+			started = false
 		case esc:
 			// This little lexer only cares about constructing the lines
 			// correctly, so everything else gets passed through.
@@ -134,9 +141,17 @@ Read:
 			_, err = l.sb.WriteRune(r)
 		case r == l.escchar:
 			esc = true
+			started = true
 		case !esc && r == '\n':
 			err = l.rd.UnreadRune()
 			break Read
+		case !started && !esc && r == '#':
+			inComment = true
+		case !started:
+			if !unicode.IsSpace(r) {
+				started = true
+			}
+			fallthrough
 		default:
 			_, err = l.sb.WriteRune(r)
 		}
diff --git a/rhel/dockerfile/testdata/Dockerfile-Comments b/rhel/dockerfile/testdata/Dockerfile-Comments
new file mode 100644
index 000000000..c49db4575
--- /dev/null
+++ b/rhel/dockerfile/testdata/Dockerfile-Comments
@@ -0,0 +1,9 @@
+# Normal comments are fine
+FROM scratch
+
+LABEL \
+	# This style of comment is buck wild, but allowed.
+	A=B \
+	C=D
+	# This comment is stripped despite the apparent continuation
+
diff --git a/rhel/dockerfile/testdata/Dockerfile-Comments.want b/rhel/dockerfile/testdata/Dockerfile-Comments.want
new file mode 100644
index 000000000..6a87d4ec9
--- /dev/null
+++ b/rhel/dockerfile/testdata/Dockerfile-Comments.want
@@ -0,0 +1,4 @@
+{
+  "A": "B",
+  "C": "D"
+}
diff --git a/rhel/dockerfile/testdata/Dockerfile-InvalidLabel b/rhel/dockerfile/testdata/Dockerfile-InvalidLabel
new file mode 100644
index 000000000..aac0f91bf
--- /dev/null
+++ b/rhel/dockerfile/testdata/Dockerfile-InvalidLabel
@@ -0,0 +1,2 @@
+LABEL A=B \
+	C=D # Comments not allowed in this position
diff --git a/rhel/dockerfile/testdata/Dockerfile-InvalidLabel.want b/rhel/dockerfile/testdata/Dockerfile-InvalidLabel.want
new file mode 100644
index 000000000..6a87d4ec9
--- /dev/null
+++ b/rhel/dockerfile/testdata/Dockerfile-InvalidLabel.want
@@ -0,0 +1,4 @@
+{
+  "A": "B",
+  "C": "D"
+}
diff --git a/rhel/dockerfile/testdata/Dockerfile-InvalidLabel.want.err b/rhel/dockerfile/testdata/Dockerfile-InvalidLabel.want.err
new file mode 100644
index 000000000..d78ba18ad
--- /dev/null
+++ b/rhel/dockerfile/testdata/Dockerfile-InvalidLabel.want.err
@@ -0,0 +1 @@
+invalid syntax: `A=B 	C=D # Comments not allowed in this position`