The Vietnamese alphabets are listed in several noncontiguous Unicode ranges:
Basic Latin {U+0000..U+007F}
Latin-1 Supplement {U+0080..U+00FF}
Latin Extended-A, -B {U+0100..U+024F}
Latin Extended Additional {U+1E00..U+1EFF}
Combining Diacritical Marks {U+0300..U+036F}
aAăĂâÂbBcCdDđĐeEêÊfFgGhHiIjJkKlLmMnNoOôÔơƠpPqQrRsStTuUưƯvVwWxXyYzZ
grave, hook above, tilde, acute, dot below
breve, circumflex, horn
&A<<\u00E0<<<\u00C0<<\u1EA3<<<\u1EA2<<\u00E3<<<\u00C3<<\u00E1<<<\u00C1<<\u1EA1<<<\u1EA0
<\u0103<<<\u0102<<\u1EB1<<<\u1EB0<<\u1EB3<<<\u1EB2<<\u1EB5<<<\u1EB4<<\u1EAF<<<\u1EAE<<\u1EB7<<<\u1EB6
<\u00E2<<<\u00C2<<\u1EA7<<<\u1EA6<<\u1EA9<<<\u1EA8<<\u1EAB<<<\u1EAA<<\u1EA5<<<\u1EA4<<\u1EAD<<<\u1EAC
&D<\u0111<<<\u0110
&E<<\u00E8<<<\u00C8<<\u1EBB<<<\u1EBA<<\u1EBD<<<\u1EBC<<\u00E9<<<\u00C9<<\u1EB9<<<\u1EB8
<\u00EA<<<\u00CA<<\u1EC1<<<\u1EC0<<\u1EC3<<<\u1EC2<<\u1EC5<<<\u1EC4<<\u1EBF<<<\u1EBE<<\u1EC7<<<\u1EC6
&I<<\u00EC<<<\u00CC<<\u1EC9<<<\u1EC8<<\u0129<<<\u0128<<\u00ED<<<\u00CD<<\u1ECB<<<\u1ECA
&O<<\u00F2<<<\u00D2<<\u1ECF<<<\u1ECE<<\u00F5<<<\u00D5<<\u00F3<<<\u00D3<<\u1ECD<<<\u1ECC
<\u00F4<<<\u00D4<<\u1ED3<<<\u1ED2<<\u1ED5<<<\u1ED4<<\u1ED7<<<\u1ED6<<\u1ED1<<<\u1ED0<<\u1ED9<<<\u1ED8
<\u01A1<<<\u01A0<<\u1EDD<<<\u1EDC<<\u1EDF<<<\u1EDE<<\u1EE1<<<\u1EE0<<\u1EDB<<<\u1EDA<<\u1EE3<<<\u1EE2
&U<<\u00F9<<<\u00D9<<\u1EE7<<<\u1EE6<<\u0169<<<\u0168<<\u00FA<<<\u00DA<<\u1EE5<<<\u1EE4
<\u01B0<<<\u01AF<<\u1EEB<<<\u1EEA<<\u1EED<<<\u1EEC<<\u1EEF<<<\u1EEE<<\u1EE9<<<\u1EE8<<\u1EF1<<<\u1EF0
&Y<<\u1EF3<<<\u1EF2<<\u1EF7<<<\u1EF6<<\u1EF9<<<\u1EF8<<\u00FD<<<\u00DD<<\u1EF5<<<\u1EF4
or
&A<<à<<<À<<ả<<<Ả<<ã<<<Ã<<á<<<Á<<ạ<<<Ạ
<ă<<<Ă<<ằ<<<Ằ<<ẳ<<<Ẳ<<ẵ<<<Ẵ<<ắ<<<Ắ<<ặ<<<Ặ
<â<<<Â<<ầ<<<Ầ<<ẩ<<<Ẩ<<ẫ<<<Ẫ<<ấ<<<Ấ<<ậ<<<Ậ
&D<đ<<<Đ
&E<<è<<<È<<ẻ<<<Ẻ<<ẽ<<<Ẽ<<é<<<É<<ẹ<<<Ẹ
<ê<<<Ê<<ề<<<Ề<<ể<<<Ể<<ễ<<<Ễ<<ế<<<Ế<<ệ<<<Ệ
&I<<ì<<<Ì<<ỉ<<<Ỉ<<ĩ<<<Ĩ<<í<<<Í<<ị<<<Ị
&O<<ò<<<Ò<<ỏ<<<Ỏ<<õ<<<Õ<<ó<<<Ó<<ọ<<<Ọ
<ô<<<Ô<<ồ<<<Ồ<<ổ<<<Ổ<<ỗ<<<Ỗ<<ố<<<Ố<<ộ<<<Ộ
<ơ<<<Ơ<<ờ<<<Ờ<<ở<<<Ở<<ỡ<<<Ỡ<<ớ<<<Ớ<<ợ<<<Ợ
&U<<ù<<<Ù<<ủ<<<Ủ<<ũ<<<Ũ<<ú<<<Ú<<ụ<<<Ụ
<ư<<<Ư<<ừ<<<Ừ<<ử<<<Ử<<ữ<<<Ữ<<ứ<<<Ứ<<ự<<<Ự
&Y<<ỳ<<<Ỳ<<ỷ<<<Ỷ<<ỹ<<<Ỹ<<ý<<<Ý<<ỵ<<<Ỵ
aAàÀảẢãÃáÁạẠăĂằẰẳẲẵẴắẮặẶâÂầẦẩẨẫẪấẤậẬbBcCdDđĐeEèÈẻẺẽẼéÉẹẸêÊềỀểỂễỄếẾệỆ
fFgGhHiIìÌỉỈĩĨíÍịỊjJkKlLmMnNoOòÒỏỎõÕóÓọỌôÔồỒổỔỗỖốỐộỘơƠờỜởỞỡỠớỚợỢpPqQrRsStTu
UùÙủỦũŨúÚụỤưƯừỪửỬữỮứỨựỰvVwWxXyYỳỲỷỶỹỸýÝỵỴzZ
Vietnam Lexicography Centre (English)
Vietnamese Character Encoding
Omniglot
Ethnologue
Mimer SQL
IBM's International Components for Unicode