diff --git a/CHANGELOG.md b/CHANGELOG.md
index 253169312..830fc1d7d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,8 @@
   ([#6810](https://github.com/mitmproxy/mitmproxy/pull/6810), @mhils)
 * Fix a bug where mitmproxy would not exit when `-n` is passed.
   ([#6819](https://github.com/mitmproxy/mitmproxy/pull/6819), @mhils)
+* Set the `unbuffered` (stdout/stderr) flag for the `mitmdump` PyInstaller build.
+  ([#6821](https://github.com/mitmproxy/mitmproxy/pull/6821), @Prinzhorn)
 
 
 ## 17 April 2024: mitmproxy 10.3.0
diff --git a/release/specs/standalone.spec b/release/specs/standalone.spec
index 768b2ade0..bcc0f3b9c 100644
--- a/release/specs/standalone.spec
+++ b/release/specs/standalone.spec
@@ -7,6 +7,11 @@ for tool in ["mitmproxy", "mitmdump", "mitmweb"]:
     if tool != "mitmproxy":
         excludes.append("mitmproxy.tools.console")
 
+    options = []
+    if tool == "mitmdump":
+        # https://github.com/mitmproxy/mitmproxy/issues/6757
+        options.append(("unbuffered", None, "OPTION"))
+
     a = Analysis(
         [tool],
         excludes=excludes,
@@ -19,8 +24,8 @@ for tool in ["mitmproxy", "mitmdump", "mitmweb"]:
         a.binaries,
         a.zipfiles,
         a.datas,
-        [],
+        options,
         name=tool,
         console=True,
-        icon='icon.ico',
+        icon="icon.ico",
     )