diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1fee900..c124093 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # Changes
 
 * 2.4.next in progress
+  * Fix [#494](https://github.com/seancorfield/honeysql/issues/494) by supporting expressions in `:on-conflict` instead of just entities.
   * Address [#493](https://github.com/seancorfield/honeysql/issues/493) by clarifying use of `:values` in CTEs (using `:with`).
   * Address [#489](https://github.com/seancorfield/honeysql/issues/489) by adding more examples around `:update`.
   * Update dev/test dependencies.
diff --git a/doc/clause-reference.md b/doc/clause-reference.md
index 38ed555..2d37f38 100644
--- a/doc/clause-reference.md
+++ b/doc/clause-reference.md
@@ -1099,10 +1099,11 @@ as if they are separate clauses but they will appear
 in pairs: `ON ... DO ...`.
 
 `:on-conflict` accepts a sequence of zero or more
-SQL entities (keywords or symbols), optionally
+SQL expressions, optionally
 followed by a single SQL clause (hash map). It can also
 accept either a single SQL entity or a single SQL clause.
-The SQL entities are column names and the SQL clause can be an
+The SQL expressions can be just column names or function calls etc,
+and the SQL clause can be an
 `:on-constraint` clause or a`:where` clause.
 
 _[For convenience of use with the `on-conflict` helper, this clause can also accept any of those arguments, wrapped in a sequence; it can also accept an empty sequence, and just produce `ON CONFLICT`, so that it can be combined with other clauses directly]_
diff --git a/src/honey/sql.cljc b/src/honey/sql.cljc
index 4642810..5c7e1fb 100644
--- a/src/honey/sql.cljc
+++ b/src/honey/sql.cljc
@@ -881,23 +881,26 @@
 
 (defn- format-on-conflict [k x]
   (if (sequential? x)
-    (let [entities (take-while ident? x)
-          n (count entities)
+    (let [exprs (take-while (complement map?) x)
+          n (count exprs)
           [clause & more] (drop n x)
-          _ (when (or (seq more)
-                      (and clause (not (map? clause))))
+          _ (when (seq more)
               (throw (ex-info "unsupported :on-conflict format"
                               {:clause x})))
-          [sql & params] (when clause
-                           (format-dsl clause))]
-      (into [(str (sql-kw k)
-                  (when (pos? n)
-                    (str " ("
-                         (str/join ", " (map #'format-entity entities))
-                         ")"))
-                  (when sql
-                    (str " " sql)))]
-            params))
+          [sqls expr-params]
+          (when (seq exprs)
+            (format-expr-list exprs))
+          [sql & clause-params]
+          (when clause
+            (format-dsl clause))]
+
+      (-> [(str (sql-kw k)
+                (when (pos? n)
+                  (str " (" (str/join ", " sqls) ")"))
+                (when sql
+                  (str " " sql)))]
+          (into expr-params)
+          (into clause-params)))
     (format-on-conflict k [x])))
 
 (defn- format-do-update-set [k x]
diff --git a/test/honey/sql_test.cljc b/test/honey/sql_test.cljc
index 242d9a4..e86fef1 100644
--- a/test/honey/sql_test.cljc
+++ b/test/honey/sql_test.cljc
@@ -772,13 +772,13 @@ DO NOTHING
 INSERT INTO customers
 (name, email)
 VALUES ('Microsoft', 'hotline@microsoft.com')
-ON CONFLICT (name, email)
+ON CONFLICT (name, TRIM(email))
 DO NOTHING
 "]
          (format {:insert-into :customers
                   :columns [:name :email]
                   :values [[[:inline "Microsoft"], [:inline "hotline@microsoft.com"]]]
-                  :on-conflict [:name :email]
+                  :on-conflict [:name [:trim :email]]
                   :do-nothing true}
                  {:pretty true})))
   (is (= ["