diff --git a/lib/systems/default.nix b/lib/systems/default.nix
index 53c095711aef..72fe1f549cf3 100644
--- a/lib/systems/default.nix
+++ b/lib/systems/default.nix
@@ -23,6 +23,7 @@ let
   platforms = import ./platforms.nix { inherit lib; };
   examples = import ./examples.nix { inherit lib; };
   architectures = import ./architectures.nix { inherit lib; };
+  rustc-target-env = import ./rustc-target-env.nix;
 
   /**
     Elaborated systems contain functions, which means that they don't satisfy
@@ -449,6 +450,16 @@ let
                 else
                   final.parsed.cpu.name;
 
+              # https://doc.rust-lang.org/reference/conditional-compilation.html#target_env
+              # Accomodate system definitions written before Nixpkgs learned about target_env.
+              env =
+                if rust ? platform.env then
+                  rust.platform.env
+                else if rustc-target-env ? ${final.rust.rustcTargetSpec} then
+                  rustc-target-env.${final.rust.rustcTargetSpec}
+                else
+                  "";
+
               # https://doc.rust-lang.org/reference/conditional-compilation.html#target_os
               os =
                 if rust ? platform then
diff --git a/lib/systems/rustc-target-env.nix b/lib/systems/rustc-target-env.nix
new file mode 100644
index 000000000000..a0bb0b66dc9c
--- /dev/null
+++ b/lib/systems/rustc-target-env.nix
@@ -0,0 +1,160 @@
+# As of rustc 1.96.0. Empty `target_env` values are omitted.
+#
+# Generation script:
+# #!/bin/bash
+# rustc --print target-list | while read -r target ; do
+#     env=$(rustc --print cfg --target "$target" | grep '^target_env=' | sed 's/# ^target_env="//;s/"$//')
+#     [[ -z "$env" ]] && continue
+#     printf '  %s = "%s";\n' "$target" "$env"
+# done
+{
+  aarch64-apple-ios-macabi = "macabi";
+  aarch64-apple-ios-sim = "sim";
+  aarch64-apple-tvos-sim = "sim";
+  aarch64-apple-visionos-sim = "sim";
+  aarch64-apple-watchos-sim = "sim";
+  aarch64-pc-windows-gnullvm = "gnu";
+  aarch64-pc-windows-msvc = "msvc";
+  aarch64-unknown-linux-gnu = "gnu";
+  aarch64-unknown-linux-gnu_ilp32 = "gnu";
+  aarch64-unknown-linux-musl = "musl";
+  aarch64-unknown-linux-ohos = "ohos";
+  aarch64-unknown-managarm-mlibc = "mlibc";
+  aarch64-unknown-nto-qnx700 = "nto70";
+  aarch64-unknown-nto-qnx710 = "nto71";
+  aarch64-unknown-nto-qnx710_iosock = "nto71_iosock";
+  aarch64-unknown-nto-qnx800 = "nto80";
+  aarch64-unknown-redox = "relibc";
+  aarch64-uwp-windows-msvc = "msvc";
+  aarch64-wrs-vxworks = "gnu";
+  aarch64_be-unknown-linux-gnu = "gnu";
+  aarch64_be-unknown-linux-gnu_ilp32 = "gnu";
+  aarch64_be-unknown-linux-musl = "musl";
+  arm-unknown-linux-gnueabi = "gnu";
+  arm-unknown-linux-gnueabihf = "gnu";
+  arm-unknown-linux-musleabi = "musl";
+  arm-unknown-linux-musleabihf = "musl";
+  arm64ec-pc-windows-msvc = "msvc";
+  armeb-unknown-linux-gnueabi = "gnu";
+  armv4t-unknown-linux-gnueabi = "gnu";
+  armv5te-unknown-linux-gnueabi = "gnu";
+  armv5te-unknown-linux-musleabi = "musl";
+  armv5te-unknown-linux-uclibceabi = "uclibc";
+  armv6k-nintendo-3ds = "newlib";
+  armv7-rtems-eabihf = "newlib";
+  armv7-sony-vita-newlibeabihf = "newlib";
+  armv7-unknown-linux-gnueabi = "gnu";
+  armv7-unknown-linux-gnueabihf = "gnu";
+  armv7-unknown-linux-musleabi = "musl";
+  armv7-unknown-linux-musleabihf = "musl";
+  armv7-unknown-linux-ohos = "ohos";
+  armv7-unknown-linux-uclibceabi = "uclibc";
+  armv7-unknown-linux-uclibceabihf = "uclibc";
+  armv7-wrs-vxworks-eabihf = "gnu";
+  armv7a-vex-v5 = "v5";
+  csky-unknown-linux-gnuabiv2 = "gnu";
+  csky-unknown-linux-gnuabiv2hf = "gnu";
+  hexagon-unknown-linux-musl = "musl";
+  i386-apple-ios = "sim";
+  i586-unknown-linux-gnu = "gnu";
+  i586-unknown-linux-musl = "musl";
+  i586-unknown-redox = "relibc";
+  i686-pc-nto-qnx700 = "nto70";
+  i686-pc-windows-gnu = "gnu";
+  i686-pc-windows-gnullvm = "gnu";
+  i686-pc-windows-msvc = "msvc";
+  i686-unknown-hurd-gnu = "gnu";
+  i686-unknown-linux-gnu = "gnu";
+  i686-unknown-linux-musl = "musl";
+  i686-uwp-windows-gnu = "gnu";
+  i686-uwp-windows-msvc = "msvc";
+  i686-win7-windows-gnu = "gnu";
+  i686-win7-windows-msvc = "msvc";
+  i686-wrs-vxworks = "gnu";
+  loongarch64-unknown-linux-gnu = "gnu";
+  loongarch64-unknown-linux-musl = "musl";
+  loongarch64-unknown-linux-ohos = "ohos";
+  m68k-unknown-linux-gnu = "gnu";
+  mips-unknown-linux-gnu = "gnu";
+  mips-unknown-linux-musl = "musl";
+  mips-unknown-linux-uclibc = "uclibc";
+  mips64-openwrt-linux-musl = "musl";
+  mips64-unknown-linux-gnuabi64 = "gnu";
+  mips64-unknown-linux-muslabi64 = "musl";
+  mips64el-unknown-linux-gnuabi64 = "gnu";
+  mips64el-unknown-linux-muslabi64 = "musl";
+  mipsel-unknown-linux-gnu = "gnu";
+  mipsel-unknown-linux-musl = "musl";
+  mipsel-unknown-linux-uclibc = "uclibc";
+  mipsisa32r6-unknown-linux-gnu = "gnu";
+  mipsisa32r6el-unknown-linux-gnu = "gnu";
+  mipsisa64r6-unknown-linux-gnuabi64 = "gnu";
+  mipsisa64r6el-unknown-linux-gnuabi64 = "gnu";
+  powerpc-unknown-linux-gnu = "gnu";
+  powerpc-unknown-linux-gnuspe = "gnu";
+  powerpc-unknown-linux-musl = "musl";
+  powerpc-unknown-linux-muslspe = "musl";
+  powerpc-wrs-vxworks = "gnu";
+  powerpc-wrs-vxworks-spe = "gnu";
+  powerpc64-unknown-linux-gnu = "gnu";
+  powerpc64-unknown-linux-musl = "musl";
+  powerpc64-wrs-vxworks = "gnu";
+  powerpc64le-unknown-linux-gnu = "gnu";
+  powerpc64le-unknown-linux-musl = "musl";
+  riscv32-wrs-vxworks = "gnu";
+  riscv32gc-unknown-linux-gnu = "gnu";
+  riscv32gc-unknown-linux-musl = "musl";
+  riscv32imac-esp-espidf = "newlib";
+  riscv32imafc-esp-espidf = "newlib";
+  riscv32imc-esp-espidf = "newlib";
+  riscv64-wrs-vxworks = "gnu";
+  riscv64a23-unknown-linux-gnu = "gnu";
+  riscv64gc-unknown-linux-gnu = "gnu";
+  riscv64gc-unknown-linux-musl = "musl";
+  riscv64gc-unknown-managarm-mlibc = "mlibc";
+  riscv64gc-unknown-redox = "relibc";
+  s390x-unknown-linux-gnu = "gnu";
+  s390x-unknown-linux-musl = "musl";
+  sparc-unknown-linux-gnu = "gnu";
+  sparc64-unknown-linux-gnu = "gnu";
+  thumbv7a-pc-windows-msvc = "msvc";
+  thumbv7a-uwp-windows-msvc = "msvc";
+  thumbv7neon-unknown-linux-gnueabihf = "gnu";
+  thumbv7neon-unknown-linux-musleabihf = "musl";
+  wasm32-wali-linux-musl = "musl";
+  wasm32-wasip1 = "p1";
+  wasm32-wasip1-threads = "p1";
+  wasm32-wasip2 = "p2";
+  wasm32-wasip3 = "p3";
+  x86_64-apple-ios = "sim";
+  x86_64-apple-ios-macabi = "macabi";
+  x86_64-apple-tvos = "sim";
+  x86_64-apple-watchos-sim = "sim";
+  x86_64-fortanix-unknown-sgx = "sgx";
+  x86_64-pc-nto-qnx710 = "nto71";
+  x86_64-pc-nto-qnx710_iosock = "nto71_iosock";
+  x86_64-pc-nto-qnx800 = "nto80";
+  x86_64-pc-windows-gnu = "gnu";
+  x86_64-pc-windows-gnullvm = "gnu";
+  x86_64-pc-windows-msvc = "msvc";
+  x86_64-unikraft-linux-musl = "musl";
+  x86_64-unknown-hurd-gnu = "gnu";
+  x86_64-unknown-l4re-uclibc = "uclibc";
+  x86_64-unknown-linux-gnu = "gnu";
+  x86_64-unknown-linux-gnuasan = "gnu";
+  x86_64-unknown-linux-gnumsan = "gnu";
+  x86_64-unknown-linux-gnutsan = "gnu";
+  x86_64-unknown-linux-gnux32 = "gnu";
+  x86_64-unknown-linux-musl = "musl";
+  x86_64-unknown-linux-ohos = "ohos";
+  x86_64-unknown-managarm-mlibc = "mlibc";
+  x86_64-unknown-redox = "relibc";
+  x86_64-uwp-windows-gnu = "gnu";
+  x86_64-uwp-windows-msvc = "msvc";
+  x86_64-win7-windows-gnu = "gnu";
+  x86_64-win7-windows-msvc = "msvc";
+  x86_64-wrs-vxworks = "gnu";
+  xtensa-esp32-espidf = "newlib";
+  xtensa-esp32s2-espidf = "newlib";
+  xtensa-esp32s3-espidf = "newlib";
+}
diff --git a/pkgs/build-support/rust/build-rust-crate/configure-crate.nix b/pkgs/build-support/rust/build-rust-crate/configure-crate.nix
index 060ce25df8db..6d7b530454d9 100644
--- a/pkgs/build-support/rust/build-rust-crate/configure-crate.nix
+++ b/pkgs/build-support/rust/build-rust-crate/configure-crate.nix
@@ -148,7 +148,7 @@ in
   export CARGO_CFG_TARGET_OS=${stdenv.hostPlatform.rust.platform.os}
   export CARGO_CFG_TARGET_FAMILY="unix"
   export CARGO_CFG_UNIX=1
-  export CARGO_CFG_TARGET_ENV="gnu"
+  export CARGO_CFG_TARGET_ENV=${stdenv.hostPlatform.rust.platform.env}
   export CARGO_CFG_TARGET_ENDIAN=${
     if stdenv.hostPlatform.parsed.cpu.significantByte.name == "littleEndian" then "little" else "big"
   }
diff --git a/pkgs/build-support/rust/build-rust-crate/test/default.nix b/pkgs/build-support/rust/build-rust-crate/test/default.nix
index 7e05e49072ab..b0f9dd4190f8 100644
--- a/pkgs/build-support/rust/build-rust-crate/test/default.nix
+++ b/pkgs/build-support/rust/build-rust-crate/test/default.nix
@@ -1008,6 +1008,66 @@ rec {
         ];
       };
 
+      crateWasm32TargetEnv = assertOutputs {
+        name = "gnu64-crate-target-env";
+        mkCrate = mkCrate pkgsCross.wasm32-unknown-none.buildRustCrate;
+        crateArgs = {
+          crateName = "wasm32-crate-target-env";
+          crateBin = [ { name = "wasm32-crate-target-env"; } ];
+          src = symlinkJoin {
+            name = "wasm32-crate-target-env-sources";
+            paths = [
+              (mkFile "build.rs" ''
+                fn main() {
+                  assert_eq!(std::env::var("CARGO_CFG_TARGET_ENV"), Ok("".to_string()));
+                }
+              '')
+              (mkFile "src/main.rs" ''
+                use std::env;
+                #[cfg(target_env = "")]
+                fn main() {
+                  let name: String = env::args().nth(0).unwrap();
+                  println!("executed {}", name);
+                }
+              '')
+            ];
+          };
+        };
+        expectedFiles = [
+          "./bin/wasm32-crate-target-env.wasm"
+        ];
+      };
+
+      crateGnu64TargetEnv = assertOutputs {
+        name = "gnu64-crate-target-env";
+        mkCrate = mkCrate pkgsCross.gnu64.buildRustCrate;
+        crateArgs = {
+          crateName = "gnu64-crate-target-env";
+          crateBin = [ { name = "gnu64-crate-target-env"; } ];
+          src = symlinkJoin {
+            name = "gnu64-crate-target-env-sources";
+            paths = [
+              (mkFile "build.rs" ''
+                fn main() {
+                  assert_eq!(std::env::var("CARGO_CFG_TARGET_ENV"), Ok("gnu".to_string()));
+                }
+              '')
+              (mkFile "src/main.rs" ''
+                use std::env;
+                #[cfg(target_env = "gnu")]
+                fn main() {
+                  let name: String = env::args().nth(0).unwrap();
+                  println!("executed {}", name);
+                }
+              '')
+            ];
+          };
+        };
+        expectedFiles = [
+          "./bin/gnu64-crate-target-env"
+        ];
+      };
+
       brotliTest =
         let
           pkg = brotliCrates.brotli_2_5_0 { };