diff --git a/crates/uv-dev/src/resolve_cli.rs b/crates/uv-dev/src/resolve_cli.rs
index 89678f071..c5a130a5d 100644
--- a/crates/uv-dev/src/resolve_cli.rs
+++ b/crates/uv-dev/src/resolve_cli.rs
@@ -45,7 +45,7 @@ pub(crate) struct ResolveCliArgs {
     exclude_newer: Option<DateTime<Utc>>,
     #[clap(long, short, default_value = IndexUrl::Pypi.as_str(), env = "UV_INDEX_URL")]
     index_url: IndexUrl,
-    #[clap(long)]
+    #[clap(long, env = "UV_EXTRA_INDEX_URL")]
     extra_index_url: Vec<IndexUrl>,
     #[clap(long)]
     find_links: Vec<FlatIndexLocation>,
diff --git a/crates/uv/src/main.rs b/crates/uv/src/main.rs
index e019dab23..ff521c56d 100644
--- a/crates/uv/src/main.rs
+++ b/crates/uv/src/main.rs
@@ -238,7 +238,7 @@ struct PipCompileArgs {
     index_url: IndexUrl,
 
     /// Extra URLs of package indexes to use, in addition to `--index-url`.
-    #[clap(long)]
+    #[clap(long, env = "UV_EXTRA_INDEX_URL")]
     extra_index_url: Vec<IndexUrl>,
 
     /// Ignore the registry index (e.g., PyPI), instead relying on direct URL dependencies and those
@@ -362,7 +362,7 @@ struct PipSyncArgs {
     index_url: IndexUrl,
 
     /// Extra URLs of package indexes to use, in addition to `--index-url`.
-    #[clap(long)]
+    #[clap(long, env = "UV_EXTRA_INDEX_URL")]
     extra_index_url: Vec<IndexUrl>,
 
     /// Locations to search for candidate distributions, beyond those found in the indexes.
@@ -527,7 +527,7 @@ struct PipInstallArgs {
     index_url: IndexUrl,
 
     /// Extra URLs of package indexes to use, in addition to `--index-url`.
-    #[clap(long)]
+    #[clap(long, env = "UV_EXTRA_INDEX_URL")]
     extra_index_url: Vec<IndexUrl>,
 
     /// Locations to search for candidate distributions, beyond those found in the indexes.
@@ -656,7 +656,7 @@ struct VenvArgs {
     index_url: IndexUrl,
 
     /// Extra URLs of package indexes to use, in addition to `--index-url`.
-    #[clap(long)]
+    #[clap(long, env = "UV_EXTRA_INDEX_URL")]
     extra_index_url: Vec<IndexUrl>,
 
     /// Ignore the registry index (e.g., PyPI), instead relying on direct URL dependencies and those