diff --git a/src/schema/rules/files/raw/task.yaml b/src/schema/rules/files/raw/task.yaml
index 1fe1712915..2e9af4b397 100644
--- a/src/schema/rules/files/raw/task.yaml
+++ b/src/schema/rules/files/raw/task.yaml
@@ -37,6 +37,7 @@ timeseries:
     acquisition: optional
     run: optional
     recording: optional
+    modality: optional
 
 timeseries__mri_no_task:
   suffixes: