diff --git a/bazel/api_build_system.bzl b/bazel/api_build_system.bzl
index b7c0b2fd..d025904c 100644
--- a/bazel/api_build_system.bzl
+++ b/bazel/api_build_system.bzl
@@ -1,5 +1,5 @@
 load("@com_envoyproxy_protoc_gen_validate//bazel:pgv_proto_library.bzl", "pgv_cc_proto_library")
-load("@com_google_protobuf//:protobuf.bzl", _py_proto_library = "py_proto_library")
+load("@rules_python//python:proto.bzl", _py_proto_library = "py_proto_library")
 load("@io_bazel_rules_go//go:def.bzl", "go_test")
 load("@io_bazel_rules_go//proto:def.bzl", "go_grpc_library", "go_proto_library")
 load("@rules_proto//proto:defs.bzl", "proto_library")
@@ -43,66 +43,24 @@ def _go_proto_mapping(dep):
 def _cc_proto_mapping(dep):
     return _proto_mapping(dep, EXTERNAL_PROTO_CC_BAZEL_DEP_MAP, _CC_PROTO_SUFFIX)
 
-def _py_proto_mapping(dep):
-    return _proto_mapping(dep, EXTERNAL_PROTO_PY_BAZEL_DEP_MAP, _PY_PROTO_SUFFIX)
-
-# TODO(htuch): Convert this to native py_proto_library once
-# https://github.com/bazelbuild/bazel/issues/3935 and/or
-# https://github.com/bazelbuild/bazel/issues/2626 are resolved.
 def _xds_py_proto_library(name, srcs = [], deps = []):
-    mapped_deps = [_py_proto_mapping(dep) for dep in deps]
-    mapped_unique_deps = []
-    [mapped_unique_deps.append(d) for d in mapped_deps if d not in mapped_unique_deps]
     _py_proto_library(
         name = name + _PY_PROTO_SUFFIX,
-        srcs = srcs,
-        default_runtime = "@com_google_protobuf//:protobuf_python",
-        protoc = "@com_google_protobuf//:protoc",
-        deps = mapped_unique_deps + [
-            "@com_envoyproxy_protoc_gen_validate//validate:validate_py",
-            "@com_google_googleapis//google/rpc:status_py_proto",
-            "@com_google_googleapis//google/api:annotations_py_proto",
-            "@com_google_googleapis//google/api:http_py_proto",
-            "@com_google_googleapis//google/api:httpbody_py_proto",
+        deps = deps + [
+            "@com_google_googleapis//google/api:http_proto",
         ],
         visibility = ["//visibility:public"],
     )
 
-# This defines googleapis py_proto_library. The repository does not provide its definition and requires
-# overriding it in the consuming project (see https://github.com/grpc/grpc/issues/19255 for more details).
-def py_proto_library(name, deps = [], plugin = None):
-    srcs = [dep[:-6] + ".proto" if dep.endswith("_proto") else dep for dep in deps]
-    proto_deps = []
-
-    # py_proto_library in googleapis specifies *_proto rules in dependencies.
-    # By rewriting *_proto to *.proto above, the dependencies in *_proto rules are not preserved.
-    # As a workaround, manually specify the proto dependencies for the imported python rules.
-    if name == "annotations_py_proto":
-        proto_deps = proto_deps + [":http_py_proto"]
-
-    # checked.proto depends on syntax.proto, we have to add this dependency manually as well.
-    if name == "checked_py_proto":
-        proto_deps = proto_deps + [":syntax_py_proto"]
-
-    # Special handling for expr_proto target
-    if srcs[0] == ":expr_moved.proto":
-        srcs = ["checked.proto", "eval.proto", "explain.proto", "syntax.proto", "value.proto",]
-        proto_deps = proto_deps + ["@com_google_googleapis//google/rpc:status_py_proto"]
-
-
-    # py_proto_library does not support plugin as an argument yet at gRPC v1.25.0:
-    # https://github.com/grpc/grpc/blob/v1.25.0/bazel/python_rules.bzl#L72.
-    # plugin should also be passed in here when gRPC version is greater than v1.25.x.
+def cc_proto_library(name, deps = [], **kwargs):
+    native.cc_proto_library(name=name, deps=deps, **kwargs)
     _py_proto_library(
-        name = name,
-        srcs = srcs,
-        default_runtime = "@com_google_protobuf//:protobuf_python",
-        protoc = "@com_google_protobuf//:protoc",
-        deps = proto_deps + ["@com_google_protobuf//:protobuf_python"],
+        name = name.replace('_cc_proto', '') + "_py_pb2",
+        deps = deps,
         visibility = ["//visibility:public"],
     )
 
-def _xds_cc_py_proto_library(
+def _xds_cc_proto_library(
         name,
         visibility = ["//visibility:private"],
         srcs = [],
@@ -129,7 +87,6 @@ def _xds_cc_py_proto_library(
         deps = [relative_name],
         visibility = ["//visibility:public"],
     )
-    _xds_py_proto_library(name, srcs, deps)
 
     # Optionally define gRPC services
     if has_services:
@@ -146,7 +103,7 @@ def xds_proto_package(
         srcs = native.glob(["*.proto"])
 
     name = "pkg"
-    _xds_cc_py_proto_library(
+    _xds_cc_proto_library(
         name = name,
         visibility = visibility,
         srcs = srcs,
@@ -154,6 +111,8 @@ def xds_proto_package(
         has_services = has_services,
     )
 
+    _xds_py_proto_library(name = name, srcs = srcs, deps = deps)
+
     compilers = ["@io_bazel_rules_go//proto:go_proto", "//bazel:pgv_plugin_go"]
     if has_services:
         compilers = ["@io_bazel_rules_go//proto:go_grpc", "//bazel:pgv_plugin_go"]
diff --git a/bazel/dependency_imports.bzl b/bazel/dependency_imports.bzl
index c617cf3f..fa0a5fbe 100644
--- a/bazel/dependency_imports.bzl
+++ b/bazel/dependency_imports.bzl
@@ -3,11 +3,17 @@ load("@bazel_gazelle//:deps.bzl", "gazelle_dependencies", "go_repository")
 load("@com_google_googleapis//:repository_rules.bzl", "switched_rules_by_language")
 load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_dependencies")
 load("@com_envoyproxy_protoc_gen_validate//bazel:repositories.bzl", "pgv_dependencies")
+load("@rules_python//python:repositories.bzl", "py_repositories")
+load("@rules_proto//proto:repositories.bzl", "rules_proto_dependencies", "rules_proto_toolchains")
+
 
 # go version for rules_go
 GO_VERSION = "1.20.2"
 
 def xds_dependency_imports(go_version = GO_VERSION):
+    py_repositories()
+    rules_proto_dependencies()
+    rules_proto_toolchains()
     protobuf_deps()
     go_rules_dependencies()
     go_register_toolchains(go_version)
@@ -20,7 +26,7 @@ def xds_dependency_imports(go_version = GO_VERSION):
         go = True,
         grpc = True,
         rules_override = {
-            "py_proto_library": ["@com_github_cncf_xds//bazel:api_build_system.bzl", "",],
+            "cc_proto_library": ["@com_github_cncf_xds//bazel:api_build_system.bzl", "",],
         },
     )
 
diff --git a/bazel/external_proto_deps.bzl b/bazel/external_proto_deps.bzl
index 4d95ab2b..728dd956 100644
--- a/bazel/external_proto_deps.bzl
+++ b/bazel/external_proto_deps.bzl
@@ -29,16 +29,18 @@ EXTERNAL_PROTO_GO_BAZEL_DEP_MAP = {
     #    go_googleapis in https://github.com/bazelbuild/rules_go/blob/master/go/dependencies.rst#overriding-dependencies
     "@com_google_googleapis//google/api/expr/v1alpha1:checked_proto": "@go_googleapis//google/api/expr/v1alpha1:expr_go_proto",
     "@com_google_googleapis//google/api/expr/v1alpha1:syntax_proto": "@go_googleapis//google/api/expr/v1alpha1:expr_go_proto",
+    "@dev_cel//proto/cel/expr:checked_proto": "@dev_cel//proto/cel/expr:checked_go_proto",
+    "@dev_cel//proto/cel/expr:syntax_proto": "@dev_cel//proto/cel/expr:syntax_go_proto",
 }
 
 # This maps from the Bazel proto_library target to the C++ language binding target for external dependencies.
 EXTERNAL_PROTO_CC_BAZEL_DEP_MAP = {
     "@com_google_googleapis//google/api/expr/v1alpha1:checked_proto": "@com_google_googleapis//google/api/expr/v1alpha1:checked_cc_proto",
     "@com_google_googleapis//google/api/expr/v1alpha1:syntax_proto": "@com_google_googleapis//google/api/expr/v1alpha1:syntax_cc_proto",
+    "@dev_cel//proto/cel/expr:checked_proto": "@dev_cel//proto/cel/expr:checked_cc_proto",
+    "@dev_cel//proto/cel/expr:syntax_proto": "@dev_cel//proto/cel/expr:syntax_cc_proto",
 }
 
 # This maps from the Bazel proto_library target to the Python language binding target for external dependencies.
 EXTERNAL_PROTO_PY_BAZEL_DEP_MAP = {
-    "@com_google_googleapis//google/api/expr/v1alpha1:checked_proto": "@com_google_googleapis//google/api/expr/v1alpha1:expr_py_proto",
-    "@com_google_googleapis//google/api/expr/v1alpha1:syntax_proto": "@com_google_googleapis//google/api/expr/v1alpha1:expr_py_proto",
 }
diff --git a/bazel/repositories.bzl b/bazel/repositories.bzl
index 3ab16c58..94798358 100644
--- a/bazel/repositories.bzl
+++ b/bazel/repositories.bzl
@@ -22,10 +22,22 @@ def xds_api_dependencies():
         "com_google_protobuf",
         locations = REPOSITORY_LOCATIONS,
     )
+    xds_http_archive(
+        name = "dev_cel",
+        locations = REPOSITORY_LOCATIONS,
+    )
     xds_http_archive(
         "io_bazel_rules_go",
         locations = REPOSITORY_LOCATIONS,
     )
+    xds_http_archive(
+        "rules_python",
+        locations = REPOSITORY_LOCATIONS,
+    )
+    xds_http_archive(
+        "rules_proto",
+        locations = REPOSITORY_LOCATIONS,
+    )
 
 # Old name for backward compatibility.
 # TODO(roth): Remove once all callers are updated to use the new name.
diff --git a/bazel/repository_locations.bzl b/bazel/repository_locations.bzl
index 080f504e..8243e939 100644
--- a/bazel/repository_locations.bzl
+++ b/bazel/repository_locations.bzl
@@ -24,9 +24,14 @@ REPOSITORY_LOCATIONS = dict(
         urls = ["https://github.com/googleapis/googleapis/archive/114a745b2841a044e98cdbb19358ed29fcf4a5f1.tar.gz"],
     ),
     com_google_protobuf = dict(
-        sha256 = "52b6160ae9266630adb5e96a9fc645215336371a740e87d411bfb63ea2f268a0",
+        sha256 = "bb1ddd8172b745cbdc75f06841bd9e7c9de0b3956397723d883423abfab8e176",
         strip_prefix = "protobuf-3.18.0",
-        urls = ["https://github.com/protocolbuffers/protobuf/releases/download/v3.18.0/protobuf-all-3.18.0.tar.gz"],
+        urls = ["https://github.com/protocolbuffers/protobuf/archive/refs/tags/v3.18.0.zip"],
+    ),
+    dev_cel = dict(
+        sha256 = "3de60ea3a29b6246faf04d206b7ee4633c155042e040086205c83edf713aee29",
+        strip_prefix = "cel-spec-2657e88023e5e7dfbb62e74de7a7cfd6e8284d7b",
+        urls = ["https://github.com/google/cel-spec/archive/2657e88023e5e7dfbb62e74de7a7cfd6e8284d7b.zip"],
     ),
     io_bazel_rules_go = dict(
         sha256 = "6dc2da7ab4cf5d7bfc7c949776b1b7c733f05e56edc4bcd9022bb249d2e2a996",
@@ -35,4 +40,15 @@ REPOSITORY_LOCATIONS = dict(
             "https://github.com/bazelbuild/rules_go/releases/download/v0.39.1/rules_go-v0.39.1.zip",
         ],
     ),
+    # used by dev_cel
+    rules_python = dict(
+        sha256 = "9d04041ac92a0985e344235f5d946f71ac543f1b1565f2cdbc9a2aaee8adf55b",
+        strip_prefix = "rules_python-0.26.0",
+        urls = ["https://github.com/bazelbuild/rules_python/releases/download/0.26.0/rules_python-0.26.0.tar.gz"],
+    ),
+    rules_proto = dict(
+        sha256 = "dc3fb206a2cb3441b485eb1e423165b231235a1ea9b031b4433cf7bc1fa460dd",
+        strip_prefix = "rules_proto-5.3.0-21.7",
+        urls = ["https://github.com/bazelbuild/rules_proto/archive/refs/tags/5.3.0-21.7.tar.gz"],
+    ),
 )
diff --git a/go/xds/type/v3/cel.pb.go b/go/xds/type/v3/cel.pb.go
index f033ccd8..be0e0c01 100644
--- a/go/xds/type/v3/cel.pb.go
+++ b/go/xds/type/v3/cel.pb.go
@@ -7,6 +7,7 @@
 package v3
 
 import (
+	expr "cel.dev/expr"
 	_ "github.com/cncf/xds/go/xds/annotations/v3"
 	_ "github.com/envoyproxy/protoc-gen-validate/validate"
 	wrappers "github.com/golang/protobuf/ptypes/wrappers"
@@ -33,6 +34,8 @@ type CelExpression struct {
 	//
 	//	*CelExpression_ParsedExpr
 	//	*CelExpression_CheckedExpr
+	//	*CelExpression_CelExprParsed
+	//	*CelExpression_CelExprChecked
 	ExprSpecifier isCelExpression_ExprSpecifier `protobuf_oneof:"expr_specifier"`
 }
 
@@ -89,6 +92,20 @@ func (x *CelExpression) GetCheckedExpr() *v1alpha1.CheckedExpr {
 	return nil
 }
 
+func (x *CelExpression) GetCelExprParsed() *expr.ParsedExpr {
+	if x, ok := x.GetExprSpecifier().(*CelExpression_CelExprParsed); ok {
+		return x.CelExprParsed
+	}
+	return nil
+}
+
+func (x *CelExpression) GetCelExprChecked() *expr.CheckedExpr {
+	if x, ok := x.GetExprSpecifier().(*CelExpression_CelExprChecked); ok {
+		return x.CelExprChecked
+	}
+	return nil
+}
+
 type isCelExpression_ExprSpecifier interface {
 	isCelExpression_ExprSpecifier()
 }
@@ -101,10 +118,22 @@ type CelExpression_CheckedExpr struct {
 	CheckedExpr *v1alpha1.CheckedExpr `protobuf:"bytes,2,opt,name=checked_expr,json=checkedExpr,proto3,oneof"`
 }
 
+type CelExpression_CelExprParsed struct {
+	CelExprParsed *expr.ParsedExpr `protobuf:"bytes,3,opt,name=cel_expr_parsed,json=celExprParsed,proto3,oneof"`
+}
+
+type CelExpression_CelExprChecked struct {
+	CelExprChecked *expr.CheckedExpr `protobuf:"bytes,4,opt,name=cel_expr_checked,json=celExprChecked,proto3,oneof"`
+}
+
 func (*CelExpression_ParsedExpr) isCelExpression_ExprSpecifier() {}
 
 func (*CelExpression_CheckedExpr) isCelExpression_ExprSpecifier() {}
 
+func (*CelExpression_CelExprParsed) isCelExpression_ExprSpecifier() {}
+
+func (*CelExpression_CelExprChecked) isCelExpression_ExprSpecifier() {}
+
 type CelExtractString struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -170,40 +199,51 @@ var file_xds_type_v3_cel_proto_rawDesc = []byte{
 	0x68, 0x65, 0x63, 0x6b, 0x65, 0x64, 0x2e, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x1a, 0x25, 0x67, 0x6f,
 	0x6f, 0x67, 0x6c, 0x65, 0x2f, 0x61, 0x70, 0x69, 0x2f, 0x65, 0x78, 0x70, 0x72, 0x2f, 0x76, 0x31,
 	0x61, 0x6c, 0x70, 0x68, 0x61, 0x31, 0x2f, 0x73, 0x79, 0x6e, 0x74, 0x61, 0x78, 0x2e, 0x70, 0x72,
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 }
 
 var (
@@ -224,18 +264,22 @@ var file_xds_type_v3_cel_proto_goTypes = []interface{}{
 	(*CelExtractString)(nil),     // 1: xds.type.v3.CelExtractString
 	(*v1alpha1.ParsedExpr)(nil),  // 2: google.api.expr.v1alpha1.ParsedExpr
 	(*v1alpha1.CheckedExpr)(nil), // 3: google.api.expr.v1alpha1.CheckedExpr
-	(*wrappers.StringValue)(nil), // 4: google.protobuf.StringValue
+	(*expr.ParsedExpr)(nil),      // 4: cel.expr.ParsedExpr
+	(*expr.CheckedExpr)(nil),     // 5: cel.expr.CheckedExpr
+	(*wrappers.StringValue)(nil), // 6: google.protobuf.StringValue
 }
 var file_xds_type_v3_cel_proto_depIdxs = []int32{
 	2, // 0: xds.type.v3.CelExpression.parsed_expr:type_name -> google.api.expr.v1alpha1.ParsedExpr
 	3, // 1: xds.type.v3.CelExpression.checked_expr:type_name -> google.api.expr.v1alpha1.CheckedExpr
-	0, // 2: xds.type.v3.CelExtractString.expr_extract:type_name -> xds.type.v3.CelExpression
-	4, // 3: xds.type.v3.CelExtractString.default_value:type_name -> google.protobuf.StringValue
-	4, // [4:4] is the sub-list for method output_type
-	4, // [4:4] is the sub-list for method input_type
-	4, // [4:4] is the sub-list for extension type_name
-	4, // [4:4] is the sub-list for extension extendee
-	0, // [0:4] is the sub-list for field type_name
+	4, // 2: xds.type.v3.CelExpression.cel_expr_parsed:type_name -> cel.expr.ParsedExpr
+	5, // 3: xds.type.v3.CelExpression.cel_expr_checked:type_name -> cel.expr.CheckedExpr
+	0, // 4: xds.type.v3.CelExtractString.expr_extract:type_name -> xds.type.v3.CelExpression
+	6, // 5: xds.type.v3.CelExtractString.default_value:type_name -> google.protobuf.StringValue
+	6, // [6:6] is the sub-list for method output_type
+	6, // [6:6] is the sub-list for method input_type
+	6, // [6:6] is the sub-list for extension type_name
+	6, // [6:6] is the sub-list for extension extendee
+	0, // [0:6] is the sub-list for field type_name
 }
 
 func init() { file_xds_type_v3_cel_proto_init() }
@@ -272,6 +316,8 @@ func file_xds_type_v3_cel_proto_init() {
 	file_xds_type_v3_cel_proto_msgTypes[0].OneofWrappers = []interface{}{
 		(*CelExpression_ParsedExpr)(nil),
 		(*CelExpression_CheckedExpr)(nil),
+		(*CelExpression_CelExprParsed)(nil),
+		(*CelExpression_CelExprChecked)(nil),
 	}
 	type x struct{}
 	out := protoimpl.TypeBuilder{
diff --git a/go/xds/type/v3/cel.pb.validate.go b/go/xds/type/v3/cel.pb.validate.go
index c28fb4ed..66795d2f 100644
--- a/go/xds/type/v3/cel.pb.validate.go
+++ b/go/xds/type/v3/cel.pb.validate.go
@@ -67,6 +67,30 @@ func (m *CelExpression) Validate() error {
 			}
 		}
 
+	case *CelExpression_CelExprParsed:
+
+		if v, ok := interface{}(m.GetCelExprParsed()).(interface{ Validate() error }); ok {
+			if err := v.Validate(); err != nil {
+				return CelExpressionValidationError{
+					field:  "CelExprParsed",
+					reason: "embedded message failed validation",
+					cause:  err,
+				}
+			}
+		}
+
+	case *CelExpression_CelExprChecked:
+
+		if v, ok := interface{}(m.GetCelExprChecked()).(interface{ Validate() error }); ok {
+			if err := v.Validate(); err != nil {
+				return CelExpressionValidationError{
+					field:  "CelExprChecked",
+					reason: "embedded message failed validation",
+					cause:  err,
+				}
+			}
+		}
+
 	default:
 		return CelExpressionValidationError{
 			field:  "ExprSpecifier",
diff --git a/xds/type/v3/BUILD b/xds/type/v3/BUILD
index e3393d99..51b75ce5 100644
--- a/xds/type/v3/BUILD
+++ b/xds/type/v3/BUILD
@@ -7,5 +7,7 @@ xds_proto_package(
         "//xds/annotations/v3:pkg",
         "@com_google_googleapis//google/api/expr/v1alpha1:checked_proto",
         "@com_google_googleapis//google/api/expr/v1alpha1:syntax_proto",
+        "@dev_cel//proto/cel/expr:checked_proto",
+        "@dev_cel//proto/cel/expr:syntax_proto",
     ],
 )
diff --git a/xds/type/v3/cel.proto b/xds/type/v3/cel.proto
index 71f6cbaf..f8740a21 100644
--- a/xds/type/v3/cel.proto
+++ b/xds/type/v3/cel.proto
@@ -4,6 +4,8 @@ package xds.type.v3;
 
 import "google/api/expr/v1alpha1/checked.proto";
 import "google/api/expr/v1alpha1/syntax.proto";
+import "cel/expr/checked.proto";
+import "cel/expr/syntax.proto";
 import "google/protobuf/wrappers.proto";
 
 import "xds/annotations/v3/status.proto";
@@ -30,6 +32,12 @@ message CelExpression {
 
     // Parsed expression in abstract syntax tree (AST) form that has been successfully type checked.
     google.api.expr.v1alpha1.CheckedExpr checked_expr = 2;
+
+    // Parsed expression in abstract syntax tree (AST) form.
+    cel.expr.ParsedExpr cel_expr_parsed = 3;
+
+    // Parsed expression in abstract syntax tree (AST) form that has been successfully type checked.
+    cel.expr.CheckedExpr cel_expr_checked = 4;
   }
 }