diff --git a/src/mime/quotedprintable/example_test.go b/src/mime/quotedprintable/example_test.go
index 1ef841ed5c..5a9ab450a3 100644
--- a/src/mime/quotedprintable/example_test.go
+++ b/src/mime/quotedprintable/example_test.go
@@ -15,7 +15,7 @@ import (
 func ExampleNewReader() {
 	for _, s := range []string{
 		`=48=65=6C=6C=6F=2C=20=47=6F=70=68=65=72=73=21`,
-		`invalid escape: =B`,
+		`invalid escape: <b style="font-size: 200%">hello</b>`,
 		"Hello, Gophers! This symbol will be unescaped: =3D and this will be written in =\r\none line.",
 	} {
 		b, err := ioutil.ReadAll(quotedprintable.NewReader(strings.NewReader(s)))
@@ -23,7 +23,7 @@ func ExampleNewReader() {
 	}
 	// Output:
 	// Hello, Gophers! <nil>
-	// invalid escape:  unexpected EOF
+	// invalid escape: <b style="font-size: 200%">hello</b> <nil>
 	// Hello, Gophers! This symbol will be unescaped: = and this will be written in one line. <nil>
 }
 
diff --git a/src/mime/quotedprintable/reader.go b/src/mime/quotedprintable/reader.go
index 7645777ab2..b142240343 100644
--- a/src/mime/quotedprintable/reader.go
+++ b/src/mime/quotedprintable/reader.go
@@ -77,6 +77,8 @@ func (r *Reader) Read(p []byte) (n int, err error) {
 	// 3. it accepts soft line-break (=) at end of message (issue 15486); i.e.
 	//    the final byte read from the underlying reader is allowed to be '=',
 	//    and it will be silently ignored.
+	// 4. it takes = as literal = if not followed by two hex digits
+	//    but not at end of line (issue 13219).
 	for len(p) > 0 {
 		if len(r.line) == 0 {
 			if r.rerr != nil {
@@ -111,6 +113,11 @@ func (r *Reader) Read(p []byte) (n int, err error) {
 		case b == '=':
 			b, err = readHexByte(r.line[1:])
 			if err != nil {
+				if len(r.line) >= 2 && r.line[1] != '\r' && r.line[1] != '\n' {
+					// Take the = as a literal =.
+					b = '='
+					break
+				}
 				return n, err
 			}
 			r.line = r.line[2:] // 2 of the 3; other 1 is done below
diff --git a/src/mime/quotedprintable/reader_test.go b/src/mime/quotedprintable/reader_test.go
index 966f33e6c0..ca016f969a 100644
--- a/src/mime/quotedprintable/reader_test.go
+++ b/src/mime/quotedprintable/reader_test.go
@@ -30,7 +30,7 @@ func TestReader(t *testing.T) {
 		{in: "foo bar=3d", want: "foo bar="}, // lax.
 		{in: "foo bar=\n", want: "foo bar"},
 		{in: "foo bar\n", want: "foo bar\n"}, // somewhat lax.
-		{in: "foo bar=0", want: "foo bar", err: io.ErrUnexpectedEOF},
+		{in: "foo bar=0", want: "foo bar=0"}, // lax
 		{in: "foo bar=0D=0A", want: "foo bar\r\n"},
 		{in: " A B        \r\n C ", want: " A B\r\n C"},
 		{in: " A B =\r\n C ", want: " A B  C"},
@@ -194,13 +194,10 @@ func TestExhaustive(t *testing.T) {
 	}
 	sort.Strings(outcomes)
 	got := strings.Join(outcomes, "\n")
-	want := `OK: 21576
-invalid bytes after =: 3397
-quotedprintable: invalid hex byte 0x0a: 1400
-quotedprintable: invalid hex byte 0x0d: 2700
-quotedprintable: invalid hex byte 0x20: 2490
-quotedprintable: invalid hex byte 0x3d: 440
-unexpected EOF: 3122`
+	want := `OK: 28934
+invalid bytes after =: 3949
+quotedprintable: invalid hex byte 0x0d: 2048
+unexpected EOF: 194`
 	if got != want {
 		t.Errorf("Got:\n%s\nWant:\n%s", got, want)
 	}