diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb960db..be822e7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changes
 
+* 2.4.next in progress
+  * Address [#504](https://github.com/seancorfield/honeysql/issues/504) by adding special syntax for ignore/respect nulls. More work will be needed to support distinct/order by/limit in BigQuery array aggregation.
+
 * 2.4.1066 -- 2023-08-27
   * Add `:select` with function call and alias example to README (PR [#502](https://github.com/seancorfield/honeysql/pull/502) [@markbastian](https://github.com/markbastian)).
   * Address [#501](https://github.com/seancorfield/honeysql/issues/501) by making `INSERT INTO` (and `REPLACE INTO`) use the `:columns` or `:values` clauses to produce column names (which are then omitted from those other clauses).
diff --git a/doc/special-syntax.md b/doc/special-syntax.md
index 6f6e3de..009e2ba 100644
--- a/doc/special-syntax.md
+++ b/doc/special-syntax.md
@@ -215,6 +215,18 @@ FROM aa
 100]
 ```
 
+## ignore/respect nulls
+
+Both of these accept a single argument -- an expression -- and
+renders that expression followed by `IGNORE NULLS` or `RESPECT NULLS`:
+
+```clojure
+(sql/format-expr [:array_agg [:ignore-nulls :a]])
+;;=> ["ARRAY_AGG(a IGNORE NULLS)"]
+(sql/format-expr [:array_agg [:respect-nulls :a]])
+;;=> ["ARRAY_AGG(a RESPECT NULLS)"]
+```
+
 ## inline
 
 Accepts a single argument and tries to render it as a
diff --git a/src/honey/sql.cljc b/src/honey/sql.cljc
index 07c2e8c..4926b7a 100644
--- a/src/honey/sql.cljc
+++ b/src/honey/sql.cljc
@@ -1605,6 +1605,10 @@
         (into paramsx)
         (into params))))
 
+(defn ignore-respect-nulls [k [x]]
+  (let [[sql & params] (format-expr x)]
+    (into [(str sql " " (sql-kw k))] params)))
+
 (def ^:private special-syntax
   (atom
    {;; these "functions" are mostly used in column
@@ -1686,6 +1690,7 @@
             (into params-p)
             (into params-e))))
     :filter expr-clause-pairs
+    :ignore-nulls ignore-respect-nulls
     :inline
     (fn [_ [x]]
       (binding [*inline* true]
@@ -1766,6 +1771,7 @@
         (raw-render (first xs))
         ;; ...but allow for multiple arguments now:
         (raw-render xs)))
+    :respect-nulls ignore-respect-nulls
     :within-group expr-clause-pairs}))
 
 (defn- format-equality-expr [op' op expr nested]