diff --git a/CHANGELOG.md b/CHANGELOG.md
index ee0a89f6..ecdc4f48 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 - Fixed duplicate keys preservation of JSON data. ([#1163](https://github.com/httpie/httpie/issues/1163))
 - Added support for formatting & coloring of JSON bodies preceded by non-JSON data (e.g., an XXSI prefix). ([#1130](https://github.com/httpie/httpie/issues/1130))
+- Installed plugins are now listed in `--debug` output. ([#1165](https://github.com/httpie/httpie/issues/1165))
 
 ## [2.5.0](https://github.com/httpie/httpie/compare/2.4.0...2.5.0) (2021-09-06)
 
diff --git a/docs/README.md b/docs/README.md
index 8814114b..c578afad 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -1200,7 +1200,6 @@ Use one of these options to control output processing:
 | `--pretty=format` | Apply formatting                                              |
 |   `--pretty=none` | Disables output processing. Default for redirected output     |
 
-
 Formatting has the following effects:
 
 - HTTP headers are sorted by name.
diff --git a/httpie/core.py b/httpie/core.py
index 9c9e3ce4..c3567219 100644
--- a/httpie/core.py
+++ b/httpie/core.py
@@ -227,6 +227,8 @@ def print_debug_info(env: Environment):
     ])
     env.stderr.write('\n\n')
     env.stderr.write(repr(env))
+    env.stderr.write('\n\n')
+    env.stderr.write(repr(plugin_manager))
     env.stderr.write('\n')
 
 
diff --git a/httpie/plugins/manager.py b/httpie/plugins/manager.py
index 23acd53f..420fb36b 100644
--- a/httpie/plugins/manager.py
+++ b/httpie/plugins/manager.py
@@ -4,6 +4,7 @@ from typing import Dict, List, Type
 
 from pkg_resources import iter_entry_points
 
+from ..utils import repr_dict
 from . import AuthPlugin, ConverterPlugin, FormatterPlugin
 from .base import BasePlugin, TransportPlugin
 
@@ -65,5 +66,13 @@ class PluginManager(list):
     def get_transport_plugins(self) -> List[Type[TransportPlugin]]:
         return self.filter(TransportPlugin)
 
+    def __str__(self):
+        return repr_dict({
+            'adapters': self.get_transport_plugins(),
+            'auth': self.get_auth_plugins(),
+            'converters': self.get_converters(),
+            'formatters': self.get_formatters(),
+        })
+
     def __repr__(self):
-        return f'<PluginManager: {list(self)}>'
+        return f'<{type(self).__name__} {self}>'