diff --git a/sklearn/linear_model/_ridge.py b/sklearn/linear_model/_ridge.py
index 199a1cd760660..f3f1074312f60 100644
--- a/sklearn/linear_model/_ridge.py
+++ b/sklearn/linear_model/_ridge.py
@@ -1466,7 +1466,7 @@ def fit(self, X, y, sample_weight=None):
 
         if np.any(self.alphas <= 0):
             raise ValueError(
-                "alphas must be positive. Got {} containing some "
+                "alphas must be strictly positive. Got {} containing some "
                 "negative or null value instead.".format(self.alphas))
 
         X, y, X_offset, y_offset, X_scale = LinearModel._preprocess_data(
diff --git a/sklearn/linear_model/tests/test_ridge.py b/sklearn/linear_model/tests/test_ridge.py
index 7d52de903aee5..2da9a60fb301e 100644
--- a/sklearn/linear_model/tests/test_ridge.py
+++ b/sklearn/linear_model/tests/test_ridge.py
@@ -1126,13 +1126,13 @@ def test_ridgecv_negative_alphas():
     # Negative integers
     ridge = RidgeCV(alphas=(-1, -10, -100))
     assert_raises_regex(ValueError,
-                        "alphas must be positive",
+                        "alphas must be strictly positive",
                         ridge.fit, X, y)
 
     # Negative floats
     ridge = RidgeCV(alphas=(-0.1, -1.0, -10.0))
     assert_raises_regex(ValueError,
-                        "alphas must be positive",
+                        "alphas must be strictly positive",
                         ridge.fit, X, y)