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diff --git a/bazel/cython_library.bzl b/bazel/cython_library.bzl
new file mode 100644
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+"""Custom rules for gRPC Python"""
+
+
+# Adapted with modifications from
+# tensorflow/tensorflow/core/platform/default/build_config.bzl
+# Native Bazel rules don't exist yet to compile Cython code, but rules have
+# been written at cython/cython and tensorflow/tensorflow. We branch from
+# Tensorflow's version as it is more actively maintained and works for gRPC
+# Python's needs.
+def pyx_library(name, deps=[], py_deps=[], srcs=[], **kwargs):
+    """Compiles a group of .pyx / .pxd / .py files.
+
+    First runs Cython to create .cpp files for each input .pyx or .py + .pxd
+    pair. Then builds a shared object for each, passing "deps" to each cc_binary
+    rule (includes Python headers by default). Finally, creates a py_library rule
+    with the shared objects and any pure Python "srcs", with py_deps as its
+    dependencies; the shared objects can be imported like normal Python files.
+
+    Args:
+        name: Name for the rule.
+        deps: C/C++ dependencies of the Cython (e.g. Numpy headers).
+        py_deps: Pure Python dependencies of the final library.
+        srcs: .py, .pyx, or .pxd files to either compile or pass through.
+        **kwargs: Extra keyword arguments passed to the py_library.
+    """
+    # First filter out files that should be run compiled vs. passed through.
+    py_srcs = []
+    pyx_srcs = []
+    pxd_srcs = []
+    for src in srcs:
+        if src.endswith(".pyx") or (src.endswith(".py") and
+                                    src[:-3] + ".pxd" in srcs):
+            pyx_srcs.append(src)
+        elif src.endswith(".py"):
+            py_srcs.append(src)
+        else:
+            pxd_srcs.append(src)
+        if src.endswith("__init__.py"):
+            pxd_srcs.append(src)
+
+    # Invoke cython to produce the shared object libraries.
+    for filename in pyx_srcs:
+        native.genrule(
+            name=filename + "_cython_translation",
+            srcs=[filename],
+            outs=[filename.split(".")[0] + ".cpp"],
+            # Optionally use PYTHON_BIN_PATH on Linux platforms so that python 3
+            # works. Windows has issues with cython_binary so skip PYTHON_BIN_PATH.
+            cmd=
+            "PYTHONHASHSEED=0 $(location @cython//:cython_binary) --cplus $(SRCS) --output-file $(OUTS)",
+            tools=["@cython//:cython_binary"] + pxd_srcs,
+        )
+
+    shared_objects = []
+    for src in pyx_srcs:
+        stem = src.split(".")[0]
+        shared_object_name = stem + ".so"
+        native.cc_binary(
+            name=shared_object_name,
+            srcs=[stem + ".cpp"],
+            deps=deps + ["@local_config_python//:python_headers"],
+            linkshared=1,
+        )
+        shared_objects.append(shared_object_name)
+
+    # Now create a py_library with these shared objects as data.
+    native.py_library(
+        name=name,
+        srcs=py_srcs,
+        deps=py_deps,
+        srcs_version="PY2AND3",
+        data=shared_objects,
+        **kwargs)
+