diff --git a/README.md b/README.md
index bc1cd8aab..7244f25ae 100644
--- a/README.md
+++ b/README.md
@@ -502,6 +502,8 @@ uv accepts the following command-line arguments as environment variables:
   index URLs, rather than limiting its search to the first index URL that contains the package.
 - `UV_REQUIRE_HASHES`: Equivalent to the `--require-hashes` command-line argument. If set to `true`,
   uv will require that all dependencies have a hash specified in the requirements file.
+- 'UV_CONSTRAINT': Equivalent to the `--constraint` command-line argument. If set, uv will use this
+  file as the constraints file. Uses space-separated list of files.
 
 In each case, the corresponding command-line argument takes precedence over an environment variable.
 
diff --git a/crates/uv/src/cli.rs b/crates/uv/src/cli.rs
index 3555a5556..069e38836 100644
--- a/crates/uv/src/cli.rs
+++ b/crates/uv/src/cli.rs
@@ -224,6 +224,18 @@ fn parse_index_url(input: &str) -> Result<Maybe<IndexUrl>, String> {
     }
 }
 
+/// Parse a string into a [`PathBuf`], mapping the empty string to `None`.
+fn parse_file_path(input: &str) -> Result<Maybe<PathBuf>, String> {
+    if input.is_empty() {
+        Ok(Maybe::None)
+    } else {
+        match PathBuf::from_str(input) {
+            Ok(path) => Ok(Maybe::Some(path)),
+            Err(err) => Err(err.to_string()),
+        }
+    }
+}
+
 #[derive(Args)]
 #[allow(clippy::struct_excessive_bools)]
 pub(crate) struct PipCompileArgs {
@@ -240,8 +252,8 @@ pub(crate) struct PipCompileArgs {
     /// trigger the installation of that package.
     ///
     /// This is equivalent to pip's `--constraint` option.
-    #[arg(long, short)]
-    pub(crate) constraint: Vec<PathBuf>,
+    #[arg(long, short, env = "UV_CONSTRAINT", value_delimiter = ' ', value_parser = parse_file_path)]
+    pub(crate) constraint: Vec<Maybe<PathBuf>>,
 
     /// Override versions using the given requirements files.
     ///
@@ -869,8 +881,8 @@ pub(crate) struct PipInstallArgs {
     /// trigger the installation of that package.
     ///
     /// This is equivalent to pip's `--constraint` option.
-    #[arg(long, short)]
-    pub(crate) constraint: Vec<PathBuf>,
+    #[arg(long, short, env = "UV_CONSTRAINT", value_delimiter = ' ', value_parser = parse_file_path)]
+    pub(crate) constraint: Vec<Maybe<PathBuf>>,
 
     /// Override versions using the given requirements files.
     ///
diff --git a/crates/uv/src/settings.rs b/crates/uv/src/settings.rs
index ba936a9ec..5a302fada 100644
--- a/crates/uv/src/settings.rs
+++ b/crates/uv/src/settings.rs
@@ -154,7 +154,10 @@ impl PipCompileSettings {
         Self {
             // CLI-only settings.
             src_file,
-            constraint,
+            constraint: constraint
+                .into_iter()
+                .filter_map(Maybe::into_option)
+                .collect(),
             r#override,
             refresh: Refresh::from_args(refresh, refresh_package),
             upgrade: Upgrade::from_args(upgrade, upgrade_package),
@@ -393,7 +396,10 @@ impl PipInstallSettings {
             package,
             requirement,
             editable,
-            constraint,
+            constraint: constraint
+                .into_iter()
+                .filter_map(Maybe::into_option)
+                .collect(),
             r#override,
             upgrade: Upgrade::from_args(upgrade, upgrade_package),
             reinstall: Reinstall::from_args(reinstall, reinstall_package),