diff --git a/news/strictly-increasing-squeeze.rst b/news/strictly-increasing-squeeze.rst
new file mode 100644
index 0000000..f14fabf
--- /dev/null
+++ b/news/strictly-increasing-squeeze.rst
@@ -0,0 +1,23 @@
+**Added:**
+
+* Raise ``ValueError`` if ``x_squeezed`` is not strictly increasing.
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>
diff --git a/src/diffpy/morph/morphs/morphsqueeze.py b/src/diffpy/morph/morphs/morphsqueeze.py
index 401d334..a6b0aac 100644
--- a/src/diffpy/morph/morphs/morphsqueeze.py
+++ b/src/diffpy/morph/morphs/morphsqueeze.py
@@ -83,6 +83,15 @@ def morph(self, x_morph, y_morph, x_target, y_target):
         coeffs = [self.squeeze[f"a{i}"] for i in range(len(self.squeeze))]
         squeeze_polynomial = Polynomial(coeffs)
         x_squeezed = self.x_morph_in + squeeze_polynomial(self.x_morph_in)
+        strictly_increasing_x = (np.diff(x_squeezed) > 0).all()
+        if not strictly_increasing_x:
+            raise ValueError(
+                "Computed squeezed x is not strictly increasing. "
+                "The squeezed morph is only intended for small polynomial "
+                "stretches. Please decrease the magnitude of the polynomial "
+                "coefficients."
+            )
+
         self.squeeze_cutoff_low = min(x_squeezed)
         self.squeeze_cutoff_high = max(x_squeezed)
         self.y_morph_out = CubicSpline(x_squeezed, self.y_morph_in)(