diff --git a/pkg/mailparser/parser.go b/pkg/mailparser/parser.go
index f40e84a..49fe6a1 100644
--- a/pkg/mailparser/parser.go
+++ b/pkg/mailparser/parser.go
@@ -324,9 +324,20 @@ func decodeBody(data []byte, cte string) []byte {
 	return data
 }
 
-// decodeMIMEHeader decodes RFC 2047 encoded-word headers.
+// decodeMIMEHeader decodes RFC 2047 encoded-word headers. Go's mime package
+// only knows UTF-8/US-ASCII/ISO-8859-1 natively; CharsetReader closes that
+// gap for charsets like Windows-1252 using the same htmlindex lookup as
+// decodeCharset for the body.
 func decodeMIMEHeader(s string) string {
-	dec := new(mime.WordDecoder)
+	dec := &mime.WordDecoder{
+		CharsetReader: func(charset string, input io.Reader) (io.Reader, error) {
+			data, err := io.ReadAll(input)
+			if err != nil {
+				return nil, err
+			}
+			return bytes.NewReader(decodeCharset(data, charset)), nil
+		},
+	}
 	decoded, err := dec.DecodeHeader(s)
 	if err != nil {
 		return s