diff --git a/lists.go b/lists.go
index 59610cc..9256f5d 100644
--- a/lists.go
+++ b/lists.go
@@ -90,7 +90,7 @@ func (c *Client) DeleteList(ctx context.Context, id ID) error {
 func (c *Client) AddToList(ctx context.Context, list ID, accounts ...ID) error {
 	params := url.Values{}
 	for _, acct := range accounts {
-		params.Add("account_ids", string(acct))
+		params.Add("account_ids[]", string(acct))
 	}
 
 	return c.doAPI(ctx, http.MethodPost, fmt.Sprintf("/api/v1/lists/%s/accounts", url.PathEscape(string(list))), params, nil, nil)
@@ -100,7 +100,7 @@ func (c *Client) AddToList(ctx context.Context, list ID, accounts ...ID) error {
 func (c *Client) RemoveFromList(ctx context.Context, list ID, accounts ...ID) error {
 	params := url.Values{}
 	for _, acct := range accounts {
-		params.Add("account_ids", string(acct))
+		params.Add("account_ids[]", string(acct))
 	}
 
 	return c.doAPI(ctx, http.MethodDelete, fmt.Sprintf("/api/v1/lists/%s/accounts", url.PathEscape(string(list))), params, nil, nil)
diff --git a/lists_test.go b/lists_test.go
index b1c9e3b..b26bc4a 100644
--- a/lists_test.go
+++ b/lists_test.go
@@ -235,7 +235,7 @@ func TestAddToList(t *testing.T) {
 			http.Error(w, http.StatusText(http.StatusNotFound), http.StatusNotFound)
 			return
 		}
-		if r.PostFormValue("account_ids") != "1" {
+		if r.PostFormValue("account_ids[]") != "1" {
 			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
 			return
 		}