diff --git a/crates/uv-distribution-types/src/file.rs b/crates/uv-distribution-types/src/file.rs
index e17901f80..2d30eb0f2 100644
--- a/crates/uv-distribution-types/src/file.rs
+++ b/crates/uv-distribution-types/src/file.rs
@@ -171,6 +171,17 @@ impl UrlString {
                 .unwrap_or_else(|| self.0.clone()),
         )
     }
+
+    /// Return the [`UrlString`] with trailing slash removed.
+    #[must_use]
+    pub fn without_trailing_slash(&self) -> Self {
+        Self(
+            self.as_ref()
+                .strip_suffix('/')
+                .map(SmallString::from)
+                .unwrap_or_else(|| self.0.clone()),
+        )
+    }
 }
 
 impl AsRef<str> for UrlString {
diff --git a/crates/uv-resolver/src/lock/mod.rs b/crates/uv-resolver/src/lock/mod.rs
index 0b72014a8..d0378a3da 100644
--- a/crates/uv-resolver/src/lock/mod.rs
+++ b/crates/uv-resolver/src/lock/mod.rs
@@ -1478,9 +1478,11 @@ impl Lock {
             if let Source::Registry(index) = &package.id.source {
                 match index {
                     RegistrySource::Url(url) => {
+                        // Normalize URL before validating.
+                        let url = url.without_trailing_slash();
                         if remotes
                             .as_ref()
-                            .is_some_and(|remotes| !remotes.contains(url))
+                            .is_some_and(|remotes| !remotes.contains(&url))
                         {
                             let name = &package.id.name;
                             let version = &package
@@ -1793,7 +1795,7 @@ pub enum SatisfiesResult<'lock> {
     /// The lockfile is missing a workspace member.
     MissingRoot(PackageName),
     /// The lockfile referenced a remote index that was not provided
-    MissingRemoteIndex(&'lock PackageName, &'lock Version, &'lock UrlString),
+    MissingRemoteIndex(&'lock PackageName, &'lock Version, UrlString),
     /// The lockfile referenced a local index that was not provided
     MissingLocalIndex(&'lock PackageName, &'lock Version, &'lock Path),
     /// A package in the lockfile contains different `requires-dist` metadata than expected.
diff --git a/crates/uv/tests/it/lock.rs b/crates/uv/tests/it/lock.rs
index 3535d9a83..e0fc8749d 100644
--- a/crates/uv/tests/it/lock.rs
+++ b/crates/uv/tests/it/lock.rs
@@ -28366,3 +28366,89 @@ fn lock_with_inconsistent_trailing_slash() -> Result<()> {
 
     Ok(())
 }
+
+/// Run `uv lock --locked` with a lockfile with trailing slashes on index URLs.
+#[test]
+fn lock_with_index_trailing_slashes_in_lockfile() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["anyio"]
+
+        [[tool.uv.index]]
+        name = "pypi-proxy"
+        url = "https://pypi-proxy.fly.dev/simple"
+        "#,
+    )?;
+
+    let lock = context.temp_dir.child("uv.lock");
+    lock.write_str(r#"
+        version = 1
+        revision = 2
+        requires-python = ">=3.12"
+
+        [options]
+        exclude-newer = "2024-03-25T00:00:00Z"
+
+        [[package]]
+        name = "anyio"
+        version = "4.3.0"
+        source = { registry = "https://pypi-proxy.fly.dev/simple/" }
+        dependencies = [
+            { name = "idna" },
+            { name = "sniffio" },
+        ]
+        sdist = { url = "https://files.pythonhosted.org/packages/db/4d/3970183622f0330d3c23d9b8a5f52e365e50381fd484d08e3285104333d3/anyio-4.3.0.tar.gz", hash = "sha256:f75253795a87df48568485fd18cdd2a3fa5c4f7c5be8e5e36637733fce06fed6", size = 159642, upload-time = "2024-02-19T08:36:28.641Z" }
+        wheels = [
+            { url = "https://files.pythonhosted.org/packages/14/fd/2f20c40b45e4fb4324834aea24bd4afdf1143390242c0b33774da0e2e34f/anyio-4.3.0-py3-none-any.whl", hash = "sha256:048e05d0f6caeed70d731f3db756d35dcc1f35747c8c403364a8332c630441b8", size = 85584, upload-time = "2024-02-19T08:36:26.842Z" },
+        ]
+
+        [[package]]
+        name = "idna"
+        version = "3.6"
+        source = { registry = "https://pypi-proxy.fly.dev/simple/" }
+        sdist = { url = "https://files.pythonhosted.org/packages/bf/3f/ea4b9117521a1e9c50344b909be7886dd00a519552724809bb1f486986c2/idna-3.6.tar.gz", hash = "sha256:9ecdbbd083b06798ae1e86adcbfe8ab1479cf864e4ee30fe4e46a003d12491ca", size = 175426, upload-time = "2023-11-25T15:40:54.902Z" }
+        wheels = [
+            { url = "https://files.pythonhosted.org/packages/c2/e7/a82b05cf63a603df6e68d59ae6a68bf5064484a0718ea5033660af4b54a9/idna-3.6-py3-none-any.whl", hash = "sha256:c05567e9c24a6b9faaa835c4821bad0590fbb9d5779e7caa6e1cc4978e7eb24f", size = 61567, upload-time = "2023-11-25T15:40:52.604Z" },
+        ]
+
+        [[package]]
+        name = "project"
+        version = "0.1.0"
+        source = { virtual = "." }
+        dependencies = [
+            { name = "anyio" },
+        ]
+
+        [package.metadata]
+        requires-dist = [{ name = "anyio" }]
+
+        [[package]]
+        name = "sniffio"
+        version = "1.3.1"
+        source = { registry = "https://pypi-proxy.fly.dev/simple/" }
+        sdist = { url = "https://files.pythonhosted.org/packages/a2/87/a6771e1546d97e7e041b6ae58d80074f81b7d5121207425c964ddf5cfdbd/sniffio-1.3.1.tar.gz", hash = "sha256:f4324edc670a0f49750a81b895f35c3adb843cca46f0530f79fc1babb23789dc", size = 20372, upload-time = "2024-02-25T23:20:04.057Z" }
+        wheels = [
+            { url = "https://files.pythonhosted.org/packages/e9/44/75a9c9421471a6c4805dbf2356f7c181a29c1879239abab1ea2cc8f38b40/sniffio-1.3.1-py3-none-any.whl", hash = "sha256:2f6da418d1f1e0fddd844478f41680e794e6051915791a034ff65e5f100525a2", size = 10235, upload-time = "2024-02-25T23:20:01.196Z" },
+        ]
+        "#
+    )?;
+
+    // Run `uv lock --locked`.
+    uv_snapshot!(context.filters(), context.lock().arg("--locked"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+
+    ----- stderr -----
+    Resolved 4 packages in [TIME]
+    ");
+
+    Ok(())
+}