diff --git a/CHANGELOG.md b/CHANGELOG.md
index 50f34c6..2586118 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Next
 
+* A URL scheme no longer accepts a comma. `+-.` in the scheme check was a character range, so `,` sat between `+` and `.`. ([#199](https://github.com/python-hyper/hyperlink/issues/199))
 * CPython 3.9 added to test matrix
 
 ## 21.0.0
diff --git a/src/hyperlink/_url.py b/src/hyperlink/_url.py
index 8797b5c..636a95c 100644
--- a/src/hyperlink/_url.py
+++ b/src/hyperlink/_url.py
@@ -154,7 +154,8 @@ def __nonzero__(self):
     r"(\?(?P<query>[^#]*))?"
     r"(#(?P<fragment>.*))?$"
 )
-_SCHEME_RE = re.compile(r"^[a-zA-Z0-9+-.]*$")
+# Hyphen is last so it is a literal. "+-." would be the range from "+" to ".".
+_SCHEME_RE = re.compile(r"^[a-zA-Z0-9.+-]*$")
 _AUTHORITY_RE = re.compile(
     r"^(?:(?P<userinfo>[^@/?#]*)@)?"
     r"(?P<host>"
diff --git a/src/hyperlink/test/test_url.py b/src/hyperlink/test/test_url.py
index 37c9172..ba72dcd 100644
--- a/src/hyperlink/test/test_url.py
+++ b/src/hyperlink/test/test_url.py
@@ -1261,6 +1261,11 @@ def test_wrong_constructor(self):
         with self.assertRaises(ValueError):
             # explicitly bad scheme not allowed
             URL("HTTP_____more_like_imHoTTeP")
+        with self.assertRaises(ValueError):
+            # "+-." is not a range, so a comma is not a scheme character
+            URL(scheme="ht,tp")
+        with self.assertRaises(ValueError):
+            URL.from_text("ht,tp://example.com")
 
     def test_encoded_userinfo(self):
         # type: () -> None