diff --git a/xds/third_party/xds/import.sh b/xds/third_party/xds/import.sh
index 44f9ad12ed4..9e4bf71d52f 100755
--- a/xds/third_party/xds/import.sh
+++ b/xds/third_party/xds/import.sh
@@ -45,9 +45,12 @@ xds/core/v3/resource_locator.proto
 xds/core/v3/resource_name.proto
 xds/data/orca/v3/orca_load_report.proto
 xds/service/orca/v3/orca.proto
+xds/type/matcher/v3/cel.proto
 xds/type/matcher/v3/matcher.proto
 xds/type/matcher/v3/regex.proto
 xds/type/matcher/v3/string.proto
+xds/type/v3/cel.proto
+xds/type/matcher/v3/http_inputs.proto
 xds/type/v3/typed_struct.proto
 )
 
diff --git a/xds/third_party/xds/src/main/proto/xds/type/matcher/v3/cel.proto b/xds/third_party/xds/src/main/proto/xds/type/matcher/v3/cel.proto
new file mode 100644
index 00000000000..b1ad1faa281
--- /dev/null
+++ b/xds/third_party/xds/src/main/proto/xds/type/matcher/v3/cel.proto
@@ -0,0 +1,42 @@
+syntax = "proto3";
+
+package xds.type.matcher.v3;
+
+import "xds/annotations/v3/status.proto";
+import "xds/type/v3/cel.proto";
+
+import "validate/validate.proto";
+
+option java_package = "com.github.xds.type.matcher.v3";
+option java_outer_classname = "CelProto";
+option java_multiple_files = true;
+option go_package = "github.com/cncf/xds/go/xds/type/matcher/v3";
+
+option (xds.annotations.v3.file_status).work_in_progress = true;
+
+// [#protodoc-title: Common Expression Language (CEL) matchers]
+
+// Performs a match by evaluating a `Common Expression Language
+// <https://github.com/google/cel-spec>`_ (CEL) expression against the standardized set of
+// :ref:`HTTP attributes <arch_overview_attributes>` specified via ``HttpAttributesCelMatchInput``.
+//
+// .. attention::
+//
+//   The match is ``true``, iff the result of the evaluation is a bool AND true.
+//   In all other cases, the match is ``false``, including but not limited to: non-bool types,
+//   ``false``, ``null``,`` int(1)``, etc.
+//   In case CEL expression raises an error, the result of the evaluation is interpreted "no match".
+//
+// Refer to :ref:`Unified Matcher API <envoy_v3_api_msg_.xds.type.matcher.v3.Matcher>` documentation
+// for usage details.
+//
+// [#comment:TODO(sergiitk): Link HttpAttributesMatchInput + usage example.]
+// [#comment:TODO(sergiitk): When implemented, add the extension tag.]
+message CelMatcher {
+  // Either parsed or checked representation of the CEL program.
+  type.v3.CelExpression expr_match = 1 [(validate.rules).message = {required: true}];
+
+  // Free-form description of the CEL AST, e.g. the original expression text, to be
+  // used for debugging assistance.
+  string description = 2;
+}
diff --git a/xds/third_party/xds/src/main/proto/xds/type/matcher/v3/http_inputs.proto b/xds/third_party/xds/src/main/proto/xds/type/matcher/v3/http_inputs.proto
new file mode 100644
index 00000000000..0dd80cd6f66
--- /dev/null
+++ b/xds/third_party/xds/src/main/proto/xds/type/matcher/v3/http_inputs.proto
@@ -0,0 +1,27 @@
+syntax = "proto3";
+
+package xds.type.matcher.v3;
+
+import "xds/annotations/v3/status.proto";
+
+option java_package = "com.github.xds.type.matcher.v3";
+option java_outer_classname = "HttpInputsProto";
+option java_multiple_files = true;
+option go_package = "github.com/cncf/xds/go/xds/type/matcher/v3";
+
+option (xds.annotations.v3.file_status).work_in_progress = true;
+
+// [#protodoc-title: Common HTTP Inputs]
+
+// Specifies that matching should be performed on the set of :ref:`HTTP attributes
+// <arch_overview_attributes>`.
+//
+// The attributes will be exposed via `Common Expression Language
+// <https://github.com/google/cel-spec>`_ runtime to associated CEL matcher.
+//
+// Refer to :ref:`Unified Matcher API <envoy_v3_api_msg_.xds.type.matcher.v3.Matcher>` documentation
+// for usage details.
+//
+// [#comment:TODO(sergiitk): When implemented, add the extension tag.]
+message HttpAttributesCelMatchInput {
+}
diff --git a/xds/third_party/xds/src/main/proto/xds/type/v3/cel.proto b/xds/third_party/xds/src/main/proto/xds/type/v3/cel.proto
new file mode 100644
index 00000000000..df4f81d90d2
--- /dev/null
+++ b/xds/third_party/xds/src/main/proto/xds/type/v3/cel.proto
@@ -0,0 +1,70 @@
+syntax = "proto3";
+
+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";
+
+import "validate/validate.proto";
+
+option java_package = "com.github.xds.type.v3";
+option java_outer_classname = "CelProto";
+option java_multiple_files = true;
+option go_package = "github.com/cncf/xds/go/xds/type/v3";
+
+option (xds.annotations.v3.file_status).work_in_progress = true;
+
+// [#protodoc-title: Common Expression Language (CEL)]
+
+// Either parsed or checked representation of the `Common Expression Language
+// <https://github.com/google/cel-spec>`_ (CEL) program.
+message CelExpression {
+  oneof expr_specifier {
+    // Parsed expression in abstract syntax tree (AST) form.
+    //
+    // Deprecated -- use ``cel_expr_parsed`` field instead.
+    // If ``cel_expr_parsed`` or ``cel_expr_checked`` is set, this field is not used.
+    google.api.expr.v1alpha1.ParsedExpr parsed_expr = 1  [deprecated = true];
+
+    // Parsed expression in abstract syntax tree (AST) form that has been successfully type checked.
+    //
+    // Deprecated -- use ``cel_expr_checked`` field instead.
+    // If ``cel_expr_parsed`` or ``cel_expr_checked`` is set, this field is not used.
+    google.api.expr.v1alpha1.CheckedExpr checked_expr = 2  [deprecated = true];
+  }
+
+  // Parsed expression in abstract syntax tree (AST) form.
+  //
+  // If ``cel_expr_checked`` is set, this field is not used.
+  cel.expr.ParsedExpr cel_expr_parsed = 3;
+
+  // Parsed expression in abstract syntax tree (AST) form that has been successfully type checked.
+  //
+  // If set, takes precedence over ``cel_expr_parsed``.
+  cel.expr.CheckedExpr cel_expr_checked = 4;
+}
+
+// Extracts a string by evaluating a `Common Expression Language
+// <https://github.com/google/cel-spec>`_ (CEL) expression against the standardized set of
+// :ref:`HTTP attributes <arch_overview_attributes>`.
+//
+// .. attention::
+//
+//   Besides CEL evaluation raising an error explicitly, CEL program returning a type other than
+//   the ``string``, or not returning anything, are considered an error as well.
+//
+// [#comment:TODO(sergiitk): When implemented, add the extension tag.]
+message CelExtractString {
+  // The CEL expression used to extract a string from the CEL environment.
+  // the "subject string") that should be replaced.
+  CelExpression expr_extract = 1 [(validate.rules).message = {required: true}];
+
+  // If CEL expression evaluates to an error, this value is be returned to the caller.
+  // If not set, the error is propagated to the caller.
+  google.protobuf.StringValue default_value = 2;
+}