diff --git a/.changeset/python-stderr-deadlock-fix.md b/.changeset/python-stderr-deadlock-fix.md
new file mode 100644
index 00000000000..3eef0c3aa96
--- /dev/null
+++ b/.changeset/python-stderr-deadlock-fix.md
@@ -0,0 +1,5 @@
+---
+"@trigger.dev/python": patch
+---
+
+Fix `python.runScript()` deadlock when the Python subprocess produces more than ~64KB of stderr output. The previous implementation hardcoded `OTEL_LOG_LEVEL: "DEBUG"` in the subprocess environment, which caused OTEL-aware Python libraries (mlflow, opentelemetry-sdk, etc.) to emit verbose debug-level logging to stderr during import. Once stderr exceeded the OS pipe buffer, the Python process would block on `write()` indefinitely. Removing the hardcoded debug log level brings `runScript()` in line with `run()`, `runInline()`, and the streaming variants — none of which set `OTEL_LOG_LEVEL`.
diff --git a/packages/python/src/index.ts b/packages/python/src/index.ts
index 6924802fd88..8d68db01dd4 100644
--- a/packages/python/src/index.ts
+++ b/packages/python/src/index.ts
@@ -97,7 +97,6 @@ export const python = {
                 }=trigger,${Object.entries(taskContext.attributes)
                   .map(([key, value]) => `${key}=${value}`)
                   .join(",")}`,
-                OTEL_LOG_LEVEL: "DEBUG",
               },
             },
             throwOnError: false,