diff --git a/tests/test_svg_image.py b/tests/test_svg_image.py
index 84b8360..b296575 100644
--- a/tests/test_svg_image.py
+++ b/tests/test_svg_image.py
@@ -417,6 +417,58 @@ def test_view_box_re(self):
             (".1,0,0,0", ViewBox(0.1, 0, 0, 0)),
             ("+.1,0,0,0", ViewBox(0.1, 0, 0, 0)),
             ("-.1,0,0,0", ViewBox(-0.1, 0, 0, 0)),
+            # https://github.com/wagtail/Willow/issues/127
+            # More combinations that include scientific notation
+            (
+                "-5.000000011410315e-06 0.0 750.00001 525.000007",
+                ViewBox(-5.000000011410315e-06, 0.0, 750.00001, 525.000007),
+            ),
+            (
+                "0.0 -5.000000011410315e-06 750.00001 525.000007",
+                ViewBox(0.0, -5.000000011410315e-06, 750.00001, 525.000007),
+            ),
+            (
+                "0.0 0.0 -5.000000011410315e-06 525.000007",
+                ViewBox(0.0, 0.0, -5.000000011410315e-06, 525.000007),
+            ),
+            (
+                "0.0 0.0 750.00001 -5.000000011410315e-06",
+                ViewBox(0.0, 0.0, 750.00001, -5.000000011410315e-06),
+            ),
+            (
+                "-5.000000011410315e-06 -5.000000011410315e-06 -5.000000011410315e-06 -5.000000011410315e-06",
+                ViewBox(
+                    -5.000000011410315e-06,
+                    -5.000000011410315e-06,
+                    -5.000000011410315e-06,
+                    -5.000000011410315e-06,
+                ),
+            ),
+            (
+                "-5.000000011410315e06 0.0 750.00001 525.000007",
+                ViewBox(-5.000000011410315e06, 0.0, 750.00001, 525.000007),
+            ),
+            (
+                "0.0 -5.000000011410315e06 750.00001 525.000007",
+                ViewBox(0.0, -5.000000011410315e06, 750.00001, 525.000007),
+            ),
+            (
+                "0.0 0.0 -5.000000011410315e06 525.000007",
+                ViewBox(0.0, 0.0, -5.000000011410315e06, 525.000007),
+            ),
+            (
+                "0.0 0.0 750.00001 -5.000000011410315e06",
+                ViewBox(0.0, 0.0, 750.00001, -5.000000011410315e06),
+            ),
+            (
+                "-5.000000011410315e06 -5.000000011410315e06 -5.000000011410315e06 -5.000000011410315e06",
+                ViewBox(
+                    -5.000000011410315e06,
+                    -5.000000011410315e06,
+                    -5.000000011410315e06,
+                    -5.000000011410315e06,
+                ),
+            ),
         ]
         for value, expected in params:
             with self.subTest(value=value, expected=expected):
diff --git a/willow/svg.py b/willow/svg.py
index cf42a3b..0e69bba 100644
--- a/willow/svg.py
+++ b/willow/svg.py
@@ -117,9 +117,10 @@ class SvgWrapper:
     UNIT_RE = re.compile(r"(?:em|ex|px|in|cm|mm|pt|pc|%)$")
 
     # https://www.w3.org/TR/SVG11/types.html#DataTypeNumber
+    # https://www.w3.org/TR/2013/WD-SVG2-20130409/types.html#DataTypeNumber
     # This will exclude some inputs that Python will accept (e.g. "1.e9", "1."),
     # but for integration with other tools, we should adhere to the spec
-    NUMBER_PATTERN = r"([+-]?(?:\d*\.)?\d+(?:[Ee]\d+)?)"
+    NUMBER_PATTERN = r"([+-]?(?:\d*\.)?\d+(?:[Ee][+-]?\d+)?)"
 
     # https://www.w3.org/Graphics/SVG/1.1/coords.html#ViewBoxAttribute
     VIEW_BOX_RE = re.compile(