diff --git a/doc/manual/rl-next/deprecat-nix-path-shadow.md b/doc/manual/rl-next/deprecat-nix-path-shadow.md
new file mode 100644
index 000000000..e868d7284
--- /dev/null
+++ b/doc/manual/rl-next/deprecat-nix-path-shadow.md
@@ -0,0 +1,13 @@
+---
+synopsis: "Deprecate shadowing internal files through the Nix search path"
+issues: [998]
+cls: [4632]
+category: "Breaking Changes"
+credits: [thubrecht]
+---
+
+As Lix uses the path `<nix/fetchurl.nix>` for bootstrapping purposes, the ability to shadow it by adding `nix=/some/path` (or `/other/path` that contains a `nix` directory) to the search path is not desirable.
+
+To alleviate potential issues, Lix now emits a warning when the Nix search path contains potential shadows for internal files, which will be changed to an error in a future release.
+
+The warning can be disabled by enabling the deprecated feature `nix-path-shadow`.
diff --git a/lix/libexpr/eval.cc b/lix/libexpr/eval.cc
index 7f12867c9..aff596108 100644
--- a/lix/libexpr/eval.cc
+++ b/lix/libexpr/eval.cc
@@ -4,12 +4,14 @@
 #include "lix/libutil/archive.hh"
 #include "lix/libutil/ansicolor.hh"
 #include "lix/libutil/async.hh"
+#include "lix/libutil/deprecated-features.hh"
 #include "lix/libutil/error.hh"
 #include "lix/libutil/english.hh"
 #include "lix/libutil/fmt.hh"
 #include "lix/libexpr/primops.hh"
 #include "lix/libexpr/print-options.hh"
 #include "lix/libmain/shared.hh"
+#include "lix/libutil/logging.hh"
 #include "lix/libutil/suggestions.hh"
 #include "lix/libutil/types.hh"
 #include "lix/libstore/store-api.hh"
@@ -347,6 +349,61 @@ EvalPaths::EvalPaths(
                 allowPath(path);
         }
     }
+
+#if LIX_MAJOR >= 3 || (LIX_MAJOR == 2 && LIX_MINOR >= 96)
+#warning \
+    "The feature nix-path-shadow was deprecated in 2.95 with a warning, which needs to be turned into an error in 2.96"
+#endif
+    if (!featureSettings.isEnabled(DeprecatedFeature::NixPathShadow)) {
+        for (auto & [prefix, path] : searchPath_.elements) {
+            // Match on the 'nix' prefix
+            if (prefix.s == "nix") {
+                logWarning(
+                    {.msg = HintFmt(
+                         "The prefix '%s' is reserved for internal use by Lix in the Nix search "
+                         "path, its usage is deprecated and will be forbidden in the future.\n"
+                         "Use %s to silence this warning.\n"
+                         "This is due to adding '%s=%s' in the Nix search path, either through the "
+                         "environment variable '%s' or by passing the flag %s to the nix "
+                         "invocation.",
+                         "nix",
+                         "--extra-deprecated-features nix-path-shadow",
+                         prefix.s,
+                         path.s,
+                         "NIX_PATH",
+                         "-I"
+                     )}
+                );
+            } else
+                // Match prefixless paths that contain a `nix` directory
+                if (auto res =
+                        prefix.suffixIfPotentialMatch("nix").and_then([&](std::string_view s) {
+                            return aio.blockOn(resolveSearchPathPath(path))
+                                .and_then([&](std::string r) {
+                                    Path res = s.length() ? concatStrings(r, "/", s): r;
+
+                                    return pathExists(res) ? std::optional(res) : std::nullopt;
+                                });
+                        }))
+                {
+                    logWarning(
+                        {.msg = HintFmt(
+                             "Shadowing '%s' by configuring the nix-path is deprecated and "
+                             "will be forbidden in the future.\n"
+                             "Use %s to silence this warning.\n"
+                             "This is due to adding '%s' to the nix-path without a prefix, "
+                             "either by passing the flag '-I %s' to the nix invocation or by "
+                             "adding this path to the environment variable '%s'.",
+                             "<nix/...>",
+                             "--extra-deprecated-features nix-path-shadow",
+                             path.s,
+                             path.s,
+                             "NIX_PATH"
+                         )}
+                    );
+                }
+        }
+    }
 }
 
 Evaluator::Evaluator(
diff --git a/lix/libutil/deprecated-features/nix-path-shadow.md b/lix/libutil/deprecated-features/nix-path-shadow.md
new file mode 100644
index 000000000..34840dec1
--- /dev/null
+++ b/lix/libutil/deprecated-features/nix-path-shadow.md
@@ -0,0 +1,6 @@
+---
+name: nix-path-shadow
+internalName: NixPathShadow
+---
+
+Allows shadowing `<nix/fetchurl.nix>` by configuration of the [*nix path*](@docroot@/language/builtin-constants.html#builtins-nixPath) to a value containing `nix=/some/path`.
diff --git a/lix/libutil/meson.build b/lix/libutil/meson.build
index ec7861154..4cab67543 100644
--- a/lix/libutil/meson.build
+++ b/lix/libutil/meson.build
@@ -172,6 +172,7 @@ deprecated_feature_definitions = files(
   # keep-sorted start
   'deprecated-features/ancient-let.md',
   'deprecated-features/cr-line-endings.md',
+  'deprecated-features/nix-path-shadow.md',
   'deprecated-features/nul-bytes.md',
   'deprecated-features/rec-set-overrides.md',
   'deprecated-features/shadow-internal-symbols.md',
diff --git a/tests/functional2/lang/search-path/eval-okay-fetchurl.out.exp b/tests/functional2/lang/search-path/eval-okay-fetchurl.out.exp
new file mode 100644
index 000000000..b4b2d7b11
--- /dev/null
+++ b/tests/functional2/lang/search-path/eval-okay-fetchurl.out.exp
@@ -0,0 +1 @@
+/__corepkgs__/fetchurl.nix
diff --git a/tests/functional2/lang/search-path/eval-okay-prefixed.err.exp b/tests/functional2/lang/search-path/eval-okay-prefixed.err.exp
new file mode 100644
index 000000000..79b54f511
--- /dev/null
+++ b/tests/functional2/lang/search-path/eval-okay-prefixed.err.exp
@@ -0,0 +1,3 @@
+warning: The prefix 'nix' is reserved for internal use by Lix in the Nix search path, its usage is deprecated and will be forbidden in the future.
+         Use --extra-deprecated-features nix-path-shadow to silence this warning.
+         This is due to adding 'nix=nix-shadow' in the Nix search path, either through the environment variable 'NIX_PATH' or by passing the flag -I to the nix invocation.
diff --git a/tests/functional2/lang/search-path/eval-okay-prefixed.out.exp b/tests/functional2/lang/search-path/eval-okay-prefixed.out.exp
new file mode 100644
index 000000000..b4b2d7b11
--- /dev/null
+++ b/tests/functional2/lang/search-path/eval-okay-prefixed.out.exp
@@ -0,0 +1 @@
+/__corepkgs__/fetchurl.nix
diff --git a/tests/functional2/lang/search-path/eval-okay-prefixless.err.exp b/tests/functional2/lang/search-path/eval-okay-prefixless.err.exp
new file mode 100644
index 000000000..cd78fe0f9
--- /dev/null
+++ b/tests/functional2/lang/search-path/eval-okay-prefixless.err.exp
@@ -0,0 +1,3 @@
+warning: Shadowing '<nix/...>' by configuring the nix-path is deprecated and will be forbidden in the future.
+         Use --extra-deprecated-features nix-path-shadow to silence this warning.
+         This is due to adding 'nix-shadow' to the nix-path without a prefix, either by passing the flag '-I nix-shadow' to the nix invocation or by adding this path to the environment variable 'NIX_PATH'.
diff --git a/tests/functional2/lang/search-path/eval-okay-prefixless.out.exp b/tests/functional2/lang/search-path/eval-okay-prefixless.out.exp
new file mode 100644
index 000000000..2f823df66
--- /dev/null
+++ b/tests/functional2/lang/search-path/eval-okay-prefixless.out.exp
@@ -0,0 +1 @@
+/pwd/nix-shadow/nix/fetchurl.nix
diff --git a/tests/functional2/lang/search-path/in-fetchurl.nix b/tests/functional2/lang/search-path/in-fetchurl.nix
new file mode 100644
index 000000000..8417f2899
--- /dev/null
+++ b/tests/functional2/lang/search-path/in-fetchurl.nix
@@ -0,0 +1 @@
+<nix/fetchurl.nix>
diff --git a/tests/functional2/lang/search-path/nix-shadow/nix/fetchurl.nix b/tests/functional2/lang/search-path/nix-shadow/nix/fetchurl.nix
new file mode 100644
index 000000000..eaa3c083e
--- /dev/null
+++ b/tests/functional2/lang/search-path/nix-shadow/nix/fetchurl.nix
@@ -0,0 +1 @@
+assert false; "womp womp"
diff --git a/tests/functional2/lang/search-path/test_search_path.py b/tests/functional2/lang/search-path/test_search_path.py
index cad85b9ce..de16ddc4f 100644
--- a/tests/functional2/lang/search-path/test_search_path.py
+++ b/tests/functional2/lang/search-path/test_search_path.py
@@ -2,7 +2,7 @@ from collections.abc import Callable
 from pathlib import Path
 
 from functional2.lang.test_lang import test_eval as nix_eval
-from functional2.testlib.fixtures.file_helper import with_files, CopyTree, CopyFile, AssetSymlink
+from functional2.testlib.fixtures.file_helper import AssetSymlink, CopyFile, CopyTree, with_files
 from functional2.testlib.fixtures.nix import Nix
 from functional2.testlib.fixtures.snapshot import Snapshot
 
@@ -36,3 +36,39 @@ def test_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot])
         ],
         snapshot,
     )
+
+
+@with_files(
+    {
+        "nix-shadow": CopyTree("nix-shadow"),
+        "in.nix": CopyFile("in-fetchurl.nix"),
+        "out.exp": AssetSymlink("eval-okay-prefixed.out.exp"),
+        "err.exp": AssetSymlink("eval-okay-prefixed.err.exp"),
+    }
+)
+def test_prefixed_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]):
+    nix.env.set_env("NIX_PATH", "nix=nix-shadow")
+    nix_eval(files, nix, [], snapshot)
+
+
+@with_files(
+    {
+        "nix-shadow": CopyTree("nix-shadow"),
+        "in.nix": CopyFile("in-fetchurl.nix"),
+        "out.exp": AssetSymlink("eval-okay-prefixless.out.exp"),
+        "err.exp": AssetSymlink("eval-okay-prefixless.err.exp"),
+    }
+)
+def test_prefixless_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]):
+    nix_eval(files, nix, ["-I", "nix-shadow"], snapshot)
+
+
+@with_files(
+    {
+        "in.nix": CopyFile("in-fetchurl.nix"),
+        "out.exp": AssetSymlink("eval-okay-fetchurl.out.exp"),
+        "err.exp": AssetSymlink("eval-okay-fetchurl.err.exp"),
+    }
+)
+def test_empty_search_path(files: Path, nix: Nix, snapshot: Callable[[str], Snapshot]):
+    nix_eval(files, nix, [], snapshot)