diff --git a/strix/report/state.py b/strix/report/state.py
index 3dbc9772..e4d1a16b 100644
--- a/strix/report/state.py
+++ b/strix/report/state.py
@@ -135,6 +135,9 @@ class ReportState:
         self._sarif_repo_ctx: dict[str, Any] | None = None
         self._sarif_repo_ctx_ready: bool = False
 
+        self.posthog_scan_ended_sent: bool = False
+        self.scarf_scan_ended_sent: bool = False
+
     def get_run_dir(self) -> Path:
         if self._run_dir is None:
             run_dir_name = self.run_name if self.run_name else self.run_id
diff --git a/strix/telemetry/posthog.py b/strix/telemetry/posthog.py
index d1a9b460..566fed9b 100644
--- a/strix/telemetry/posthog.py
+++ b/strix/telemetry/posthog.py
@@ -82,6 +82,10 @@ def finding(severity: str) -> None:
 
 
 def end(report_state: "ReportState", exit_reason: str = "completed") -> None:
+    if report_state.posthog_scan_ended_sent:
+        return
+    report_state.posthog_scan_ended_sent = True
+
     vulnerabilities_counts = {"critical": 0, "high": 0, "medium": 0, "low": 0, "info": 0}
     for v in report_state.vulnerability_reports:
         sev = v.get("severity", "info").lower()
diff --git a/strix/telemetry/scarf.py b/strix/telemetry/scarf.py
index 037494bb..d3d3684e 100644
--- a/strix/telemetry/scarf.py
+++ b/strix/telemetry/scarf.py
@@ -85,6 +85,10 @@ def finding(severity: str) -> None:
 
 
 def end(report_state: ReportState, exit_reason: str = "completed") -> None:
+    if report_state.scarf_scan_ended_sent:
+        return
+    report_state.scarf_scan_ended_sent = True
+
     vulnerabilities_counts = {"critical": 0, "high": 0, "medium": 0, "low": 0, "info": 0}
     for v in report_state.vulnerability_reports:
         sev = v.get("severity", "info").lower()
diff --git a/tests/test_telemetry.py b/tests/test_telemetry.py
new file mode 100644
index 00000000..c43776bc
--- /dev/null
+++ b/tests/test_telemetry.py
@@ -0,0 +1,39 @@
+"""Tests for scan telemetry emission."""
+
+from __future__ import annotations
+
+from typing import Any
+
+import pytest
+
+from strix.report.state import ReportState
+from strix.telemetry import posthog, scarf
+
+
+@pytest.mark.parametrize(
+    ("backend", "sent_attribute"),
+    [
+        (posthog, "posthog_scan_ended_sent"),
+        (scarf, "scarf_scan_ended_sent"),
+    ],
+)
+def test_scan_ended_is_sent_once_per_backend(
+    monkeypatch: pytest.MonkeyPatch,
+    backend: Any,
+    sent_attribute: str,
+) -> None:
+    state = ReportState(run_name="test-run")
+    sent_events: list[tuple[str, dict[str, Any]]] = []
+    monkeypatch.setattr(
+        backend,
+        "_send",
+        lambda event, properties: sent_events.append((event, properties)),
+    )
+
+    backend.end(state, exit_reason="finished_by_tool")
+    backend.end(state, exit_reason="user_exit")
+
+    assert getattr(state, sent_attribute) is True
+    assert len(sent_events) == 1
+    assert sent_events[0][0] == "scan_ended"
+    assert sent_events[0][1]["exit_reason"] == "finished_by_tool"