diff --git a/dlls/vbscript/parse.h b/dlls/vbscript/parse.h
index 5f7fba2b963..0e1b4d187f4 100644
--- a/dlls/vbscript/parse.h
+++ b/dlls/vbscript/parse.h
@@ -19,6 +19,7 @@
 typedef enum {
     EXPR_BOOL,
     EXPR_MEMBER,
+    EXPR_NOT,
     EXPR_STRING
 } expression_type_t;
 
@@ -37,6 +38,11 @@ typedef struct {
     const WCHAR *value;
 } string_expression_t;
 
+typedef struct {
+    expression_t expr;
+    expression_t *subexpr;
+} unary_expression_t;
+
 typedef struct {
     expression_t expr;
     expression_t *obj_expr;
diff --git a/dlls/vbscript/parser.y b/dlls/vbscript/parser.y
index 728d69bbec4..a743b97c4c1 100644
--- a/dlls/vbscript/parser.y
+++ b/dlls/vbscript/parser.y
@@ -37,6 +37,7 @@ static void source_add_statement(parser_ctx_t*,statement_t*);
 
 static expression_t *new_bool_expression(parser_ctx_t*,VARIANT_BOOL);
 static expression_t *new_string_expression(parser_ctx_t*,const WCHAR*);
+static expression_t *new_unary_expression(parser_ctx_t*,expression_type_t,expression_t*);
 
 static member_expression_t *new_member_expression(parser_ctx_t*,expression_t*,const WCHAR*);
 
@@ -74,6 +75,7 @@ static statement_t *new_call_statement(parser_ctx_t*,member_expression_t*);
 
 %type <statement> Statement StatementNl
 %type <expression> Expression LiteralExpression PrimaryExpression
+%type <expression> NotExpression
 %type <member> MemberExpression
 %type <expression> Arguments_opt ArgumentList_opt ArgumentList
 %type <bool> OptionExplicit_opt
@@ -119,8 +121,12 @@ EmptyBrackets_opt
     | tEMPTYBRACKETS
 
 Expression
+    : NotExpression                 { $$ = $1; }
+
+NotExpression
     : LiteralExpression /* FIXME */ { $$ = $1; }
     | PrimaryExpression /* FIXME */ { $$ = $1; }
+    | tNOT NotExpression            { $$ = new_unary_expression(ctx, EXPR_NOT, $2); CHECK_ERROR; }
 
 LiteralExpression
     : tTRUE                         { $$ = new_bool_expression(ctx, VARIANT_TRUE); CHECK_ERROR; }
@@ -190,6 +196,18 @@ static expression_t *new_string_expression(parser_ctx_t *ctx, const WCHAR *value
     return &expr->expr;
 }
 
+static expression_t *new_unary_expression(parser_ctx_t *ctx, expression_type_t type, expression_t *subexpr)
+{
+    unary_expression_t *expr;
+
+    expr = new_expression(ctx, type, sizeof(*expr));
+    if(!expr)
+        return NULL;
+
+    expr->subexpr = subexpr;
+    return &expr->expr;
+}
+
 static member_expression_t *new_member_expression(parser_ctx_t *ctx, expression_t *obj_expr, const WCHAR *identifier)
 {
     member_expression_t *expr;