diff --git a/internal/toml-test/tests/invalid/string/bad-hex-esc-1.toml b/internal/toml-test/tests/invalid/string/bad-hex-esc-1.toml
new file mode 100644
index 00000000..199c9615
--- /dev/null
+++ b/internal/toml-test/tests/invalid/string/bad-hex-esc-1.toml
@@ -0,0 +1 @@
+bad-hex-esc-1 = "\x0g"
diff --git a/internal/toml-test/tests/invalid/string/bad-hex-esc-2.toml b/internal/toml-test/tests/invalid/string/bad-hex-esc-2.toml
new file mode 100644
index 00000000..3ff07653
--- /dev/null
+++ b/internal/toml-test/tests/invalid/string/bad-hex-esc-2.toml
@@ -0,0 +1 @@
+bad-hex-esc-2 = "\xG0"
diff --git a/internal/toml-test/tests/invalid/string/bad-hex-esc-3.toml b/internal/toml-test/tests/invalid/string/bad-hex-esc-3.toml
new file mode 100644
index 00000000..5a1df546
--- /dev/null
+++ b/internal/toml-test/tests/invalid/string/bad-hex-esc-3.toml
@@ -0,0 +1 @@
+bad-hex-esc-3 = "\x"
diff --git a/internal/toml-test/tests/invalid/string/bad-hex-esc-4.toml b/internal/toml-test/tests/invalid/string/bad-hex-esc-4.toml
new file mode 100644
index 00000000..4df871b6
--- /dev/null
+++ b/internal/toml-test/tests/invalid/string/bad-hex-esc-4.toml
@@ -0,0 +1 @@
+bad-hex-esc-4 = "\x 50"
diff --git a/internal/toml-test/tests/invalid/string/bad-hex-esc-5.toml b/internal/toml-test/tests/invalid/string/bad-hex-esc-5.toml
new file mode 100644
index 00000000..379922fd
--- /dev/null
+++ b/internal/toml-test/tests/invalid/string/bad-hex-esc-5.toml
@@ -0,0 +1 @@
+bad-hex-esc-5 = "\x 50"
diff --git a/internal/toml-test/tests/invalid/string/bad-hex-esc.multi b/internal/toml-test/tests/invalid/string/bad-hex-esc.multi
new file mode 100644
index 00000000..5216ce00
--- /dev/null
+++ b/internal/toml-test/tests/invalid/string/bad-hex-esc.multi
@@ -0,0 +1,4 @@
+bad-hex-esc-1 = "\x0g"
+bad-hex-esc-2 = "\xG0"
+bad-hex-esc-3 = "\x"
+bad-hex-esc-4 = "\x 50"
diff --git a/internal/toml-test/tests/valid/string/hex-escape.json b/internal/toml-test/tests/valid/string/hex-escape.json
new file mode 100644
index 00000000..0eae986c
--- /dev/null
+++ b/internal/toml-test/tests/valid/string/hex-escape.json
@@ -0,0 +1,34 @@
+{
+  "bs": {
+    "type": "string",
+    "value": ""
+  },
+  "hello": {
+    "type": "string",
+    "value": "hello\n"
+  },
+  "higher-than-127": {
+    "type": "string",
+    "value": "Sørmirbæren"
+  },
+  "literal": {
+    "type": "string",
+    "value": "\\x20 \\x09 \\x0d\\x0a"
+  },
+  "multiline": {
+    "type": "string",
+    "value": "  \t \u001b \r\n\n\n\u0000\nhello\n\nSørmirbæren\n"
+  },
+  "multiline-literal": {
+    "type": "string",
+    "value": "\\x20 \\x09 \\x0d\\x0a\n"
+  },
+  "nul": {
+    "type": "string",
+    "value": "\u0000"
+  },
+  "whitespace": {
+    "type": "string",
+    "value": "  \t \u001b \r\n"
+  }
+}
diff --git a/internal/toml-test/tests/valid/string/hex-escape.toml b/internal/toml-test/tests/valid/string/hex-escape.toml
new file mode 100644
index 00000000..26d1668f
--- /dev/null
+++ b/internal/toml-test/tests/valid/string/hex-escape.toml
@@ -0,0 +1,21 @@
+# \x for the first 255 codepoints
+
+whitespace      = "\x20 \x09 \x1b \x0d\x0a"
+bs              = "\x7f"
+nul             = "\x00"
+hello           = "\x68\x65\x6c\x6c\x6f\x0a"
+higher-than-127 = "S\xf8rmirb\xe6ren"
+
+multiline = """
+\x20 \x09 \x1b \x0d\x0a
+\x7f
+\x00
+\x68\x65\x6c\x6c\x6f\x0a
+\x53\xF8\x72\x6D\x69\x72\x62\xE6\x72\x65\x6E
+"""
+
+# Not inside literals.
+literal = '\x20 \x09 \x0d\x0a'
+multiline-literal = '''
+\x20 \x09 \x0d\x0a
+'''
diff --git a/internal/toml-test/version.go b/internal/toml-test/version.go
index 50e0e2a0..7c3cfd55 100644
--- a/internal/toml-test/version.go
+++ b/internal/toml-test/version.go
@@ -11,13 +11,15 @@ type versionSpec struct {
 var versions = map[string]versionSpec{
 	"next": versionSpec{
 		exclude: []string{
-			"invalid/datetime/no-secs", // Times without seconds is no longer invalid.
+			"invalid/datetime/no-secs",          // Times without seconds is no longer invalid.
+			"invalid/string/basic-byte-escapes", // \x is now valid.
 		},
 	},
 
 	"1.0.0": versionSpec{
 		exclude: []string{
-			"valid/string/escape-esc",   // \e
+			"valid/string/escape-esc",                               // \e
+			"valid/string/hex-escape", "invalid/string/bad-hex-esc", // \x..
 			"valid/datetime/no-seconds", // Times without seconds
 		},
 	},
diff --git a/lex.go b/lex.go
index bf2f6ae8..000ccca0 100644
--- a/lex.go
+++ b/lex.go
@@ -851,6 +851,11 @@ func lexStringEscape(lx *lexer) stateFn {
 		fallthrough
 	case '\\':
 		return lx.pop()
+	case 'x':
+		if !tomlNext {
+			return lx.error(errLexEscape{r})
+		}
+		return lexHexEscape
 	case 'u':
 		return lexShortUnicodeEscape
 	case 'U':
@@ -859,6 +864,19 @@ func lexStringEscape(lx *lexer) stateFn {
 	return lx.error(errLexEscape{r})
 }
 
+func lexHexEscape(lx *lexer) stateFn {
+	var r rune
+	for i := 0; i < 2; i++ {
+		r = lx.next()
+		if !isHexadecimal(r) {
+			return lx.errorf(
+				`expected two hexadecimal digits after '\x', but got %q instead`,
+				lx.current())
+		}
+	}
+	return lx.pop()
+}
+
 func lexShortUnicodeEscape(lx *lexer) stateFn {
 	var r rune
 	for i := 0; i < 4; i++ {
diff --git a/parse.go b/parse.go
index 2ee22970..f9b98214 100644
--- a/parse.go
+++ b/parse.go
@@ -766,6 +766,12 @@ func (p *parser) replaceEscapes(it item, str string) string {
 		case '\\':
 			replaced = append(replaced, rune(0x005C))
 			r += 1
+		case 'x':
+			if tomlNext {
+				escaped := p.asciiEscapeToUnicode(it, s[r+1:r+3])
+				replaced = append(replaced, escaped)
+				r += 3
+			}
 		case 'u':
 			// At this point, we know we have a Unicode escape of the form
 			// `uXXXX` at [r, r+5). (Because the lexer guarantees this
diff --git a/toml_test.go b/toml_test.go
index 7664c4ad..a61b911f 100644
--- a/toml_test.go
+++ b/toml_test.go
@@ -255,7 +255,8 @@ func TestTomlNext(t *testing.T) {
 func TestTomlNextFails(t *testing.T) {
 	runTomlTest(t, true,
 		"valid/string/escape-esc",
-		"valid/datetime/no-seconds")
+		"valid/datetime/no-seconds",
+		"valid/string/hex-escape")
 }
 
 func runTomlTest(t *testing.T, includeNext bool, wantFail ...string) {