diff --git a/metaflow/metaflow_config.py b/metaflow/metaflow_config.py
index e5e03a401a6..832b14c6865 100644
--- a/metaflow/metaflow_config.py
+++ b/metaflow/metaflow_config.py
@@ -476,6 +476,13 @@
 
 ARGO_WORKFLOWS_UI_URL = from_conf("ARGO_WORKFLOWS_UI_URL")
 
+# How long (in seconds) to keep completed Argo Workflows before auto-deletion.
+# Default: 7 days (same as Kubernetes jobs). Maps to Argo's ttlStrategy.
+# Set to 0 to disable TTL (workflows persist indefinitely).
+ARGO_WORKFLOWS_TTL_SECONDS_AFTER_COMPLETION = from_conf(
+    "ARGO_WORKFLOWS_TTL_SECONDS_AFTER_COMPLETION", 7 * 24 * 60 * 60
+)
+
 ##
 # Airflow Configuration
 ##
diff --git a/metaflow/plugins/argo/argo_workflows.py b/metaflow/plugins/argo/argo_workflows.py
index b7b25c8c69d..6fadb0f31f7 100644
--- a/metaflow/plugins/argo/argo_workflows.py
+++ b/metaflow/plugins/argo/argo_workflows.py
@@ -25,6 +25,7 @@
     ARGO_WORKFLOWS_CAPTURE_ERROR_SCRIPT,
     ARGO_WORKFLOWS_ENV_VARS_TO_SKIP,
     ARGO_WORKFLOWS_KUBERNETES_SECRETS,
+    ARGO_WORKFLOWS_TTL_SECONDS_AFTER_COMPLETION,
     ARGO_WORKFLOWS_UI_URL,
     AWS_SECRETS_MANAGER_DEFAULT_REGION,
     AZURE_KEY_VAULT_PREFIX,
@@ -897,6 +898,8 @@ def _compile_workflow_template(self):
                 WorkflowSpec()
                 # Set overall workflow timeout.
                 .active_deadline_seconds(self.workflow_timeout)
+                # Set TTL for completed workflows (default: 7 days).
+                .ttl_strategy(ARGO_WORKFLOWS_TTL_SECONDS_AFTER_COMPLETION)
                 # TODO: Allow Argo to optionally archive all workflow execution logs
                 #       It's disabled for now since it requires all Argo installations
                 #       to enable an artifactory repository. If log archival is
@@ -4295,6 +4298,14 @@ def hooks(self, hooks):
             self.payload["hooks"].update({k: v.to_json()})
         return self
 
+    def ttl_strategy(self, seconds_after_completion):
+        # https://argoproj.github.io/argo-workflows/fields/#ttlstrategy
+        if seconds_after_completion is not None and int(seconds_after_completion) > 0:
+            self.payload["ttlStrategy"] = {
+                "secondsAfterCompletion": int(seconds_after_completion)
+            }
+        return self
+
     def to_json(self):
         return self.payload
 
diff --git a/test/unit/test_argo_ttl_strategy.py b/test/unit/test_argo_ttl_strategy.py
new file mode 100644
index 00000000000..c32353cae8b
--- /dev/null
+++ b/test/unit/test_argo_ttl_strategy.py
@@ -0,0 +1,40 @@
+"""Tests for WorkflowSpec.ttl_strategy()."""
+
+from metaflow.plugins.argo.argo_workflows import WorkflowSpec
+
+
+def test_positive_value_sets_ttl():
+    ws = WorkflowSpec()
+    ws.ttl_strategy(604800)
+    assert ws.payload["ttlStrategy"] == {"secondsAfterCompletion": 604800}
+
+
+def test_zero_disables_ttl():
+    ws = WorkflowSpec()
+    ws.ttl_strategy(0)
+    assert "ttlStrategy" not in ws.payload
+
+
+def test_none_disables_ttl():
+    ws = WorkflowSpec()
+    ws.ttl_strategy(None)
+    assert "ttlStrategy" not in ws.payload
+
+
+def test_negative_disables_ttl():
+    ws = WorkflowSpec()
+    ws.ttl_strategy(-1)
+    assert "ttlStrategy" not in ws.payload
+
+
+def test_string_value_converted_to_int():
+    ws = WorkflowSpec()
+    ws.ttl_strategy("86400")
+    assert ws.payload["ttlStrategy"] == {"secondsAfterCompletion": 86400}
+
+
+def test_chaining():
+    """ttl_strategy returns self for method chaining."""
+    ws = WorkflowSpec()
+    result = ws.ttl_strategy(3600)
+    assert result is ws