diff --git a/zetasql/parser/bison_parser.y b/zetasql/parser/bison_parser.y
index e8c76b99..20c20656 100644
--- a/zetasql/parser/bison_parser.y
+++ b/zetasql/parser/bison_parser.y
@@ -697,6 +697,7 @@ using zetasql::ASTDropStatement;
 %token KW_IGNORE "IGNORE"
 %token KW_IN "IN"
 %token KW_INNER "INNER"
+%token KW_INSTANCE_NOT_IN_WINDOW "INSTANCE_NOT_IN_WINDOW"
 %token KW_INTERSECT "INTERSECT"
 %token KW_INTERVAL "INTERVAL"
 %token KW_INTO "INTO"
@@ -797,6 +798,7 @@ using zetasql::ASTDropStatement;
 %token KW_CONTINUE "CONTINUE"
 %token KW_CONSTANT "CONSTANT"
 %token KW_CONSTRAINT "CONSTRAINT"
+%token KW_CURRENT_TIME "CURRENT_TIME"
 %token KW_DATA "DATA"
 %token KW_DATABASE "DATABASE"
 %token KW_DATE "DATE"
@@ -1366,6 +1368,8 @@ using zetasql::ASTDropStatement;
 %type <boolean> opt_recursive
 %type <boolean> opt_unique
 %type <boolean> opt_search
+%type <boolean> opt_instance_not_in_window
+%type <boolean> opt_exclude_current_time
 %type <node> opt_with_anonymization
 %type <node> primary_key_column_attribute
 %type <node> hidden_column_attribute
@@ -6598,7 +6602,7 @@ frame_unit:
     ;
 
 opt_window_frame_clause:
-    frame_unit "BETWEEN" window_frame_bound "AND for BETWEEN" window_frame_bound opt_maxsize
+    frame_unit "BETWEEN" window_frame_bound "AND for BETWEEN" window_frame_bound opt_maxsize 
       {
         auto* frame = MAKE_NODE(ASTWindowFrame, @$, {$3, $5, $6});
         frame->set_unit($1);
@@ -6611,23 +6615,40 @@ opt_window_frame_clause:
         $$ = frame;
       }
     | /* Nothing */ { $$ = nullptr; }
-
+    ;
 opt_maxsize:
   "MAXSIZE" integer_literal
     {
       $$ = MAKE_NODE(ASTMaxSize, @$, {$2});
     }
   | /* Nothing */ { $$ = nullptr; }
-
+  ;
+opt_instance_not_in_window:
+  "INSTANCE_NOT_IN_WINDOW"
+    {
+      $$ = true;
+    };
+  | /* Nothing */ { $$ = false; }
+  ;
+opt_exclude_current_time:
+  "EXCLUDE" "CURRENT_TIME"
+    {
+      $$ = true;
+    };
+  | /* Nothing */ { $$ = false; }
+  ;
 window_specification:
     identifier
       {
         $$ = MAKE_NODE(ASTWindowSpecification, @$, {$1});
       }
     | "(" opt_identifier opt_partition_by_clause opt_order_by_clause
-          opt_window_frame_clause ")"
+          opt_window_frame_clause opt_exclude_current_time opt_instance_not_in_window ")"
       {
-        $$ = MAKE_NODE(ASTWindowSpecification, @$, {$2, $3, $4, $5});
+        auto *window_spec = MAKE_NODE(ASTWindowSpecification, @$, {$2, $3, $4, $5});
+        window_spec->set_is_exclude_current_time($6);
+        window_spec->set_is_instance_not_in_window($7);
+        $$ = window_spec;
       }
    ;
 
@@ -7009,6 +7030,7 @@ reserved_keyword_rule:
     | "IGNORE"
     | "IN"
     | "INNER"
+    | "INSTANCE_NOT_IN_WINDOW"
     | "INTERSECT"
     | "INTERVAL"
     | "INTO"
@@ -7104,6 +7126,7 @@ keyword_as_identifier:
     | "CONSTANT"
     | "CONSTRAINT"
     | "CONTINUE"
+    | "CURRENT_TIME"
     | "DATA"
     | "DATABASE"
     | "DATE"
diff --git a/zetasql/parser/flex_tokenizer.l b/zetasql/parser/flex_tokenizer.l
index 01012235..c24d0d21 100644
--- a/zetasql/parser/flex_tokenizer.l
+++ b/zetasql/parser/flex_tokenizer.l
@@ -399,6 +399,7 @@ create { return BisonParserImpl::token::KW_CREATE; }
 cross { return BisonParserImpl::token::KW_CROSS; }
 cube { return BisonParserImpl::token::KW_CUBE; }
 current { return BisonParserImpl::token::KW_CURRENT; }
+current_time { return BisonParserImpl::token::KW_CURRENT_TIME;}
 data { return BisonParserImpl::token::KW_DATA; }
 database { return BisonParserImpl::token::KW_DATABASE; }
 date { return BisonParserImpl::token::KW_DATE; }
@@ -480,6 +481,7 @@ include { return BisonParserImpl::token::KW_INCLUDE; }
 inout { return BisonParserImpl::token::KW_INOUT; }
 index { return BisonParserImpl::token::KW_INDEX; }
 inner { return BisonParserImpl::token::KW_INNER; }
+instance_not_in_window { return BisonParserImpl::token::KW_INSTANCE_NOT_IN_WINDOW; }
 insert { return BisonParserImpl::token::KW_INSERT; }
 intersect { return BisonParserImpl::token::KW_INTERSECT; }
 interval { return BisonParserImpl::token::KW_INTERVAL; }
diff --git a/zetasql/parser/keywords.cc b/zetasql/parser/keywords.cc
index a80e16c8..b9a3f9ea 100644
--- a/zetasql/parser/keywords.cc
+++ b/zetasql/parser/keywords.cc
@@ -94,6 +94,7 @@ constexpr KeywordInfoPOD kAllKeywords[] = {
     {"cross", KW_CROSS, KeywordInfo::kReserved},
     {"cube", KW_CUBE, KeywordInfo::kReserved},
     {"current", KW_CURRENT, KeywordInfo::kReserved},
+    {"current_time", KW_CURRENT_TIME},
     {"data", KW_DATA},
     {"database", KW_DATABASE},
     {"date", KW_DATE},
@@ -160,6 +161,7 @@ constexpr KeywordInfoPOD kAllKeywords[] = {
     {"index", KW_INDEX},
     {"inner", KW_INNER, KeywordInfo::kReserved},
     {"insert", KW_INSERT},
+    {"instance_not_in_window", KW_INSTANCE_NOT_IN_WINDOW, KeywordInfo::kReserved},
     {"intersect", KW_INTERSECT, KeywordInfo::kReserved},
     {"interval", KW_INTERVAL, KeywordInfo::kReserved},
     {"iterate", KW_ITERATE},
diff --git a/zetasql/parser/keywords_test.cc b/zetasql/parser/keywords_test.cc
index 422aeae0..f71129ea 100644
--- a/zetasql/parser/keywords_test.cc
+++ b/zetasql/parser/keywords_test.cc
@@ -237,7 +237,7 @@ TEST(ParserTest, DontAddNewReservedKeywords) {
   // allows new queries to work that will not work on older code.
   // Before changing this, co-ordinate with all engines to make sure the change
   // is done safely.
-  EXPECT_EQ(96 /* CAUTION */, num_reserved);
+  EXPECT_EQ(97 /* CAUTION */, num_reserved);
 }
 
 }  // namespace
diff --git a/zetasql/parser/parse_tree.cc b/zetasql/parser/parse_tree.cc
index 5651c55a..dd48240c 100644
--- a/zetasql/parser/parse_tree.cc
+++ b/zetasql/parser/parse_tree.cc
@@ -906,6 +906,21 @@ std::string ASTWindowFrame::SingleNodeDebugString() const {
   return absl::StrCat(ASTNode::SingleNodeDebugString(), "(",
                       GetFrameUnitString(), ")");
 }
+std::string ASTWindowSpecification::SingleNodeDebugString() const {
+  if (is_instance_not_in_window_ && is_exclude_current_time_) {
+    return absl::StrCat(ASTNode::SingleNodeDebugString(), 
+    "(is_exclude_current_time, is_instance_not_in_window)");
+  }
+  if (is_instance_not_in_window_) {
+    return absl::StrCat(ASTNode::SingleNodeDebugString(), 
+    "(is_instance_not_in_window)");
+  }
+  if (is_exclude_current_time_) {
+    return absl::StrCat(ASTNode::SingleNodeDebugString(), 
+    "(is_exclude_current_time)");
+  }
+  return ASTNode::SingleNodeDebugString();
+}
 
 // static
 std::string ASTWindowFrame::FrameUnitToString(FrameUnit unit) {
diff --git a/zetasql/parser/parse_tree_manual.h b/zetasql/parser/parse_tree_manual.h
index 22cc4b89..e656c623 100644
--- a/zetasql/parser/parse_tree_manual.h
+++ b/zetasql/parser/parse_tree_manual.h
@@ -2817,7 +2817,13 @@ class ASTWindowSpecification final : public ASTNode {
   const ASTWindowFrame* window_frame() const { return window_frame_; }
 
   const ASTIdentifier* base_window_name() const { return base_window_name_; }
+  
+  bool is_instance_not_in_window() const { return is_instance_not_in_window_; }
+  void set_is_instance_not_in_window(bool value) { is_instance_not_in_window_ = value; }
 
+  bool is_exclude_current_time() const { return is_exclude_current_time_; }
+  void set_is_exclude_current_time(bool value) { is_exclude_current_time_ = value; }
+  std::string SingleNodeDebugString() const override;
  private:
   void InitFields() final {
     FieldLoader fl(this);
@@ -2832,6 +2838,9 @@ class ASTWindowSpecification final : public ASTNode {
   const ASTPartitionBy* partition_by_ = nullptr;
   const ASTOrderBy* order_by_ = nullptr;
   const ASTWindowFrame* window_frame_ = nullptr;
+
+  bool is_instance_not_in_window_ = false;
+  bool is_exclude_current_time_ = false;
 };
 
 class ASTWindowDefinition final : public ASTNode {
diff --git a/zetasql/parser/testdata/analytic_functions.test b/zetasql/parser/testdata/analytic_functions.test
index 4cf56c93..cc4bc7df 100644
--- a/zetasql/parser/testdata/analytic_functions.test
+++ b/zetasql/parser/testdata/analytic_functions.test
@@ -655,6 +655,68 @@ FROM
   T
 ==
 
+# window with exclude current_time 
+select f() over (rows_range between 5s preceding and current row maxsize 5 exclude current_time)
+from T
+--
+QueryStatement [0-103]
+  Query [0-103]
+    Select [0-103]
+      SelectList [7-96]
+        SelectColumn [7-96]
+          AnalyticFunctionCall [7-96]
+            FunctionCall [7-10]
+              PathExpression [7-8]
+                Identifier(f) [7-8]
+            WindowSpecification(is_exclude_current_time) [16-96]
+              WindowFrame(ROWS_RANGE) [17-74]
+                WindowFrameExpr(OFFSET PRECEDING) [36-48]
+                  IntervalLiteral(5s) [36-38]
+                WindowFrameExpr(CURRENT ROW) [53-64]
+                MaxSize [65-74]
+                  IntLiteral(5) [73-74]
+      FromClause [97-103]
+        TablePathExpression [102-103]
+          PathExpression [102-103]
+            Identifier(T) [102-103]
+--
+SELECT
+  f() OVER (ROWS_RANGE BETWEEN 5s PRECEDING AND CURRENT ROW MAXSIZE 5 EXCLUDE CURRENT_TIME)
+FROM
+  T
+==
+
+# window with instance_not_in_window 
+select f() over (rows_range between 5s preceding and current row maxsize 5 instance_not_in_window)
+from T
+--
+QueryStatement [0-105]
+  Query [0-105]
+    Select [0-105]
+      SelectList [7-98]
+        SelectColumn [7-98]
+          AnalyticFunctionCall [7-98]
+            FunctionCall [7-10]
+              PathExpression [7-8]
+                Identifier(f) [7-8]
+            WindowSpecification(is_instance_not_in_window) [16-98]
+              WindowFrame(ROWS_RANGE) [17-74]
+                WindowFrameExpr(OFFSET PRECEDING) [36-48]
+                  IntervalLiteral(5s) [36-38]
+                WindowFrameExpr(CURRENT ROW) [53-64]
+                MaxSize [65-74]
+                  IntLiteral(5) [73-74]
+      FromClause [99-105]
+        TablePathExpression [104-105]
+          PathExpression [104-105]
+            Identifier(T) [104-105]
+--
+SELECT
+  f() OVER (ROWS_RANGE BETWEEN 5s PRECEDING AND CURRENT ROW MAXSIZE 5 INSTANCE_NOT_IN_WINDOW)
+FROM
+  T
+==
+
 select f() over (range between 5+5 preceding and current {{rows|blah}})
 from T
 --
diff --git a/zetasql/parser/unparser.cc b/zetasql/parser/unparser.cc
index 00121063..0d46a2e0 100644
--- a/zetasql/parser/unparser.cc
+++ b/zetasql/parser/unparser.cc
@@ -2111,6 +2111,13 @@ void Unparser::visitASTWindowDefinition(
 void Unparser::visitASTWindowSpecification(
     const ASTWindowSpecification* node, void* data) {
   UnparseChildrenWithSeparator(node, data, "");
+  if (node->is_exclude_current_time()) {
+    print("EXCLUDE CURRENT_TIME");
+  }
+
+  if (node->is_instance_not_in_window()) {
+    print("INSTANCE_NOT_IN_WINDOW");
+  }
 }
 
 void Unparser::visitASTPartitionBy(const ASTPartitionBy* node, void* data) {