diff --git a/meshmode/array_context.py b/meshmode/array_context.py
index 8c4a2e259b1ad5fc5969f32d256b5129de535a49..d238c72d741712540e2956fa951a0437b032394a 100644
--- a/meshmode/array_context.py
+++ b/meshmode/array_context.py
@@ -73,7 +73,7 @@ class _BaseFakeNumpyNamespace:
         "degrees", "radians", "unwrap", "deg2rad", "rad2deg",
 
         # Deprecated, for compatibility (see below)
-        "atan2",
+        "atan2", "acos",
 
         # Hyperbolic functions
         "sinh", "cosh", "tanh", "arcsinh", "arccosh", "arctanh",
@@ -239,6 +239,13 @@ class ArrayContext:
             warn("'atan2' in ArrayContext.np is deprecated. Use 'arctan2', "
                     "as in numpy2. This will be disallowed in 2021.",
                     DeprecationWarning, stacklevel=3)
+        elif name == "arccos":
+            name = "acos"
+        elif name == "acos":
+            from warnings import warn
+            warn("'acos' in ArrayContext.np is deprecated. Use 'arccos', "
+                    "as in numpy2. This will be disallowed in 2021.",
+                    DeprecationWarning, stacklevel=3)
 
         from pymbolic import var