diff --git a/build.rs b/build.rs
index e4d8088..6c30782 100644
--- a/build.rs
+++ b/build.rs
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (C) 2026, Nathan Gill
+
 use time::{OffsetDateTime, format_description::well_known::Iso8601};
 
 /// build helper for generating version strings from environment
diff --git a/src/auth_sys.rs b/src/auth_sys.rs
index 6509e0f..24d2df4 100644
--- a/src/auth_sys.rs
+++ b/src/auth_sys.rs
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (C) 2026, Nathan Gill
+
 #[cfg(not(target_os = "openbsd"))]
 mod pam_backend {
     use std::{
diff --git a/src/comm.rs b/src/comm.rs
index 4ae4afb..3db60a1 100644
--- a/src/comm.rs
+++ b/src/comm.rs
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (C) 2026, Nathan Gill
+
 use std::{
     marker::PhantomData,
     os::fd::{AsFd, OwnedFd},
diff --git a/src/event_loop.rs b/src/event_loop.rs
index 6c37a9b..7d0e7a2 100644
--- a/src/event_loop.rs
+++ b/src/event_loop.rs
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (C) 2026, Nathan Gill
+
 use std::{
     os::fd::RawFd,
     time::{Duration, Instant},
diff --git a/src/font.rs b/src/font.rs
index 1349356..a923b94 100644
--- a/src/font.rs
+++ b/src/font.rs
@@ -1,3 +1,6 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (C) 2026, Nathan Gill
+
 pub trait FontInfo {
     fn font_height(&self) -> f64;
 }