diff --git a/gen/encoder.go b/gen/encoder.go
index b2be743..037efce 100644
--- a/gen/encoder.go
+++ b/gen/encoder.go
@@ -223,7 +223,9 @@ func (g *Generator) genTypeEncoderNoCheck(t reflect.Type, in string, tags fieldT
 		fmt.Fprintln(g.out, ws+"  "+tmpVar+"First := true")
 		fmt.Fprintln(g.out, ws+"  for "+tmpVar+"Name, "+tmpVar+"Value := range "+in+" {")
 		fmt.Fprintln(g.out, ws+"    if "+tmpVar+"First { "+tmpVar+"First = false } else { out.RawByte(',') }")
-		if keyEnc != "" {
+		if key.Implements(reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()) {
+			fmt.Fprintln(g.out, ws+"    "+fmt.Sprintf("out.RawText(("+tmpVar+"Name).MarshalText()"+")"))
+		} else if keyEnc != "" {
 			fmt.Fprintln(g.out, ws+"    "+fmt.Sprintf(keyEnc, tmpVar+"Name"))
 		} else {
 			if err := g.genTypeEncoder(key, tmpVar+"Name", tags, indent+2, false); err != nil {