diff --git a/autoload/go/highlight_test.vim b/autoload/go/highlight_test.vim
index 81f6098833..1330b0b8a4 100644
--- a/autoload/go/highlight_test.vim
+++ b/autoload/go/highlight_test.vim
@@ -104,18 +104,37 @@ function! Test_numeric_literal_highlight() abort
   let tests = {
         \ 'lone zero': {'group': 'goDecimalInt', 'value': '0'},
         \ 'integer': {'group': 'goDecimalInt', 'value': '1234567890'},
+        \ 'integerGrouped': {'group': 'goDecimalInt', 'value': '1_234_567_890'},
+        \ 'integerErrorLeadingUnderscore': {'group': 'goDecimalError', 'value': '_1234_567_890'},
+        \ 'integerErrorTrailingUnderscore': {'group': 'goDecimalError', 'value': '1_234_567890_'},
+        \ 'integerErrorDoubleUnderscore': {'group': 'goDecimalError', 'value': '1_234__567_890'},
         \ 'hexadecimal': {'group': 'goHexadecimalInt', 'value': '0x0123456789abdef'},
+        \ 'hexadecimalGrouped': {'group': 'goHexadecimalInt', 'value': '0x012_345_678_9ab_def'},
         \ 'hexadecimalErrorLeading': {'group': 'goHexadecimalError', 'value': '0xg0123456789abdef'},
         \ 'hexadecimalErrorTrailing': {'group': 'goHexadecimalError', 'value': '0x0123456789abdefg'},
+        \ 'hexadecimalErrorDoubleUnderscore': {'group': 'goHexadecimalError', 'value': '0x__0123456789abdef'},
+        \ 'hexadecimalErrorTrailingUnderscore': {'group': 'goHexadecimalError', 'value': '0x0123456789abdef_'},
         \ 'heXadecimal': {'group': 'goHexadecimalInt', 'value': '0X0123456789abdef'},
         \ 'heXadecimalErrorLeading': {'group': 'goHexadecimalError', 'value': '0Xg0123456789abdef'},
         \ 'heXadecimalErrorTrailing': {'group': 'goHexadecimalError', 'value': '0X0123456789abdefg'},
         \ 'octal': {'group': 'goOctalInt', 'value': '01234567'},
+        \ 'octalPrefix': {'group': 'goOctalInt', 'value': '0o1234567'},
+        \ 'octalGrouped': {'group': 'goOctalInt', 'value': '0o1_234_567'},
         \ 'octalErrorLeading': {'group': 'goOctalError', 'value': '081234567'},
         \ 'octalErrorTrailing': {'group': 'goOctalError', 'value': '012345678'},
+        \ 'octalErrorDoubleUnderscore': {'group': 'goOctalError', 'value': '0o__1234567'},
+        \ 'octalErrorTrailingUnderscore': {'group': 'goOctalError', 'value': '0o_123456_7_'},
+        \ 'octalErrorTrailingO': {'group': 'goOctalError', 'value': '0o_123456_7o'},
+        \ 'octalErrorTrailingX': {'group': 'goOctalError', 'value': '0o_123456_7x'},
+        \ 'octalErrorTrailingB': {'group': 'goOctalError', 'value': '0o_123456_7b'},
+        \ 'OctalPrefix': {'group': 'goOctalInt', 'value': '0O1234567'},
         \ 'binaryInt': {'group': 'goBinaryInt', 'value': '0b0101'},
+        \ 'binaryIntGrouped': {'group': 'goBinaryInt', 'value': '0b_01_01'},
         \ 'binaryErrorLeading': {'group': 'goBinaryError', 'value': '0b20101'},
         \ 'binaryErrorTrailing': {'group': 'goBinaryError', 'value': '0b01012'},
+        \ 'binaryErrorDoubleUnderscore': {'group': 'goBinaryError', 'value': '0b_01__01'},
+        \ 'binaryOverrideOctal': {'group': 'goBinaryError', 'value': '0b1234567'},
+        \ 'binaryErrorTrailingUnderscore': {'group': 'goBinaryError', 'value': '0b_01_01_'},
         \ 'BinaryInt': {'group': 'goBinaryInt', 'value': '0B0101'},
         \ 'BinaryErrorLeading': {'group': 'goBinaryError', 'value': '0B20101'},
         \ 'BinaryErrorTrailing': {'group': 'goBinaryError', 'value': '0B01012'},
diff --git a/syntax/go.vim b/syntax/go.vim
index c39e044a45..60824dcec7 100644
--- a/syntax/go.vim
+++ b/syntax/go.vim
@@ -162,15 +162,17 @@ endif
 syn match       goSingleDecl        /\%(import\|var\|const\) [^(]\@=/ contains=goImport,goVar,goConst
 
 " Integers
-syn match       goDecimalInt        "\<-\=\(0\|[1-9]\d*\)\%([Ee][-+]\=\d\+\)\=\>"
-syn match       goHexadecimalInt    "\<-\=0[xX]\x\+\>"
-syn match       goHexadecimalError  "\<-\=0[xX]\x*[^ \t0-9A-Fa-f]\S*\>"
-syn match       goOctalInt          "\<-\=0\o\+\>"
-syn match       goOctalError        "\<-\=0[XxBb\]]\@!\o*[^ \t0-7]\S*\>"
-syn match       goBinaryInt         "\<-\=0[bB][01]\+\>"
-syn match       goBinaryError       "\<-\=0[bB][01]*[^ \t01]\S*\>"
+syn match       goDecimalInt        "\<-\=\(0\|[1-9]_\?\(\d\|\d\+_\?\d\+\)*\)\%([Ee][-+]\=\d\+\)\=\>"
+syn match       goDecimalError      "\<-\=\(_\(\d\+_*\)\+\|\([1-9]\d*_*\)\+__\(\d\+_*\)\+\|\([1-9]\d*_*\)\+_\+\)\%([Ee][-+]\=\d\+\)\=\>"
+syn match       goHexadecimalInt    "\<-\=0[xX]_\?\(\x\+_\?\)\+\>"
+syn match       goHexadecimalError  "\<-\=0[xX]_\?\(\x\+_\?\)*\(\([^ \t0-9A-Fa-f_]\|__\)\S*\|_\)\>"
+syn match       goOctalInt          "\<-\=0[oO]\?_\?\(\o\+_\?\)\+\>"
+syn match       goOctalError        "\<-\=0[0-7oO_]*\(\([^ \t0-7oOxX_/\]\}]\|[oO]\{2,\}\|__\)\S*\|_\|[oOxX]\)\>"
+syn match       goBinaryInt         "\<-\=0[bB]_\?\([01]\+_\?\)\+\>"
+syn match       goBinaryError       "\<-\=0[bB]_\?[01_]*\([^ \t01_]\S*\|__\S*\|_\)\>"
 
 hi def link     goDecimalInt        Integer
+hi def link     goDecimalError      Error
 hi def link     goHexadecimalInt    Integer
 hi def link     goHexadecimalError  Error
 hi def link     goOctalInt          Integer