diff --git a/src/libstore/parsed-derivations.cc b/src/libstore/parsed-derivations.cc
index f2288a04ed81..4475a8c35975 100644
--- a/src/libstore/parsed-derivations.cc
+++ b/src/libstore/parsed-derivations.cc
@@ -122,7 +122,7 @@ bool ParsedDerivation::willBuildLocally(Store & localStore) const
 
 bool ParsedDerivation::substitutesAllowed() const
 {
-    return getBoolAttr("allowSubstitutes", true);
+    return true;
 }
 
 static std::regex shVarName("[A-Za-z_][A-Za-z0-9_]*");
diff --git a/src/nix-env/buildenv.nix b/src/nix-env/buildenv.nix
index 0bac4c44b48a..1cf6dd54a673 100644
--- a/src/nix-env/buildenv.nix
+++ b/src/nix-env/buildenv.nix
@@ -20,6 +20,5 @@ derivation {
   # network traffic, so don't do that.
   preferLocalBuild = true;
 
-  # Also don't bother substituting.
-  allowSubstitutes = false;
+  allowSubstitutes = true;
 }