diff --git a/CHANGELOG.md b/CHANGELOG.md
index ba024f5e0..b79c7be1e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Fixed
 
 - Sandboxed processes sticking around after CLI is killed with a signal
+- Lockfiles with local versions breaking the pip parser
 
 ## 6.3.0 - 2024-04-18
 
diff --git a/lockfile/src/lib.rs b/lockfile/src/lib.rs
index b152c9fb2..4da82a90c 100644
--- a/lockfile/src/lib.rs
+++ b/lockfile/src/lib.rs
@@ -217,6 +217,11 @@ pub enum PackageVersion {
     Git(String),
     /// Version distributed over HTTP(S).
     DownloadUrl(String),
+    /// Untracked version source.
+    ///
+    /// Used for package versions which cannot clearly be identified, like
+    /// Python's local version.
+    Unknown,
 }
 
 /// Version from a foreign package registry.
diff --git a/lockfile/src/parse_depfile.rs b/lockfile/src/parse_depfile.rs
index effad99e5..914cbceb4 100644
--- a/lockfile/src/parse_depfile.rs
+++ b/lockfile/src/parse_depfile.rs
@@ -192,6 +192,10 @@ fn filter_packages(mut packages: Vec<Package>) -> Vec<PackageDescriptor> {
                     log::debug!("Ignoring remote dependency {} ({url:?})", package.name);
                     return None;
                 },
+                PackageVersion::Unknown => {
+                    log::debug!("Ignoring dependency {}", package.name);
+                    return None;
+                },
             };
 
             Some(PackageDescriptor {
diff --git a/lockfile/src/parsers/pypi.rs b/lockfile/src/parsers/pypi.rs
index 4064e3b5a..950bb4796 100644
--- a/lockfile/src/parsers/pypi.rs
+++ b/lockfile/src/parsers/pypi.rs
@@ -102,12 +102,17 @@ fn package<'a>(input: &'a str, registry: Option<&str>) -> IResult<&'a str, Packa
 
     // Parse first-party dependencies.
     let (input, version) = package_version(input)?;
-    let version = match registry {
-        Some(registry) => PackageVersion::ThirdParty(ThirdPartyVersion {
-            version: version.trim().into(),
+
+    // Parse local version specifier.
+    let (input, local_version) = opt(local_version)(input)?;
+
+    let version = match (registry, local_version) {
+        (_, Some(_)) => PackageVersion::Unknown,
+        (Some(registry), _) => PackageVersion::ThirdParty(ThirdPartyVersion {
+            version: local_version.unwrap_or(version).trim().into(),
             registry: registry.into(),
         }),
-        None => PackageVersion::FirstParty(version.trim().into()),
+        (None, None) => PackageVersion::FirstParty(version.trim().into()),
     };
 
     // Ensure line is empty after the dependency.
@@ -185,6 +190,15 @@ fn package_version(input: &str) -> IResult<&str, &str> {
     recognize(many1(alt((alphanumeric1, tag(".")))))(input)
 }
 
+/// Parse local version specifiers.
+///
+/// https://packaging.python.org/en/latest/specifications/version-specifiers/#local-version-identifiers
+fn local_version(input: &str) -> IResult<&str, &str> {
+    let (input, _) = tag("+")(input)?;
+
+    recognize(many1(alt((alphanumeric1, tag(".")))))(input)
+}
+
 fn identifier(input: &str) -> IResult<&str, &str> {
     recognize(pair(alphanumeric1, many0(alt((alphanumeric1, alt((tag("-"), tag("_"), tag("."))))))))(
         input,
diff --git a/lockfile/src/python.rs b/lockfile/src/python.rs
index 09b84b4f0..ec2cd25fa 100644
--- a/lockfile/src/python.rs
+++ b/lockfile/src/python.rs
@@ -238,7 +238,7 @@ mod tests {
         let pkgs = PyRequirements
             .parse(include_str!("../../tests/fixtures/requirements-locked.txt"))
             .unwrap();
-        assert_eq!(pkgs.len(), 14);
+        assert_eq!(pkgs.len(), 15);
 
         let expected_pkgs = [
             Package {
@@ -317,6 +317,11 @@ mod tests {
                 }),
                 package_type: PackageType::PyPi,
             },
+            Package {
+                name: "localversion".into(),
+                version: PackageVersion::Unknown,
+                package_type: PackageType::PyPi,
+            },
         ];
 
         for expected_pkg in expected_pkgs {
diff --git a/tests/fixtures/requirements-locked.txt b/tests/fixtures/requirements-locked.txt
index 07297db1c..ac347b86c 100644
--- a/tests/fixtures/requirements-locked.txt
+++ b/tests/fixtures/requirements-locked.txt
@@ -20,6 +20,8 @@ requests[security,tests]==2.28.1
 
 werkzeug==2.9.2 ; python_version >= "3.7" and python_version < "3.12"
 
+localversion==2.3.4+1.0.99.local
+
 attr @ file:///tmp/attr
 
 numpy @ file:///tmp/testing/numpy-1.23.5-pp38-pypy38_pp73-win_amd64.whl
diff --git a/tests/fixtures/requirements-unlocked.txt b/tests/fixtures/requirements-unlocked.txt
index 4f075a6e0..1daaf904a 100644
--- a/tests/fixtures/requirements-unlocked.txt
+++ b/tests/fixtures/requirements-unlocked.txt
@@ -32,3 +32,4 @@ FooProject8 > 1.8.*
 FooProject9 > 2.0.*, !=2.1
 FooProject10==1.2.3 --random-flag
 git+https://github.com/matiascodesal/git-for-pip-example.git@v1.0.0#egg=my-git-package
+localversion >= 2.3.4+1.0.99.local