diff --git a/jgvariant-ostree/src/main/java/eu/mulk/jgvariant/ostree/Commit.java b/jgvariant-ostree/src/main/java/eu/mulk/jgvariant/ostree/Commit.java
new file mode 100644
index 0000000..43909ba
--- /dev/null
+++ b/jgvariant-ostree/src/main/java/eu/mulk/jgvariant/ostree/Commit.java
@@ -0,0 +1,51 @@
+package eu.mulk.jgvariant.ostree;
+
+import eu.mulk.jgvariant.core.Decoder;
+import java.nio.ByteOrder;
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+
+/**
+ * A commit in an OSTree repository.
+ *
+ * <p>Has an optional parent, a root directory, and various metadata.
+ *
+ * <p>Reference: {@code ostree-core.h#OSTREE_COMMIT_GVARIANT_STRING}
+ */
+public record Commit(
+    Metadata metadata,
+    Checksum parentChecksum,
+    List<RelatedObject> relatedObjects,
+    String subject,
+    String body,
+    long timestamp,
+    Checksum rootDirTreeChecksum,
+    Checksum rootDirMetaChecksum) {
+
+  public record RelatedObject(String ref, Checksum commitChecksum) {
+
+    private static final Decoder<RelatedObject> DECODER =
+        Decoder.ofStructure(
+            RelatedObject.class, Decoder.ofString(StandardCharsets.UTF_8), Checksum.decoder());
+
+    public static Decoder<RelatedObject> decoder() {
+      return DECODER;
+    }
+  }
+
+  private static final Decoder<Commit> DECODER =
+      Decoder.ofStructure(
+          Commit.class,
+          Metadata.decoder(),
+          Checksum.decoder(),
+          Decoder.ofArray(RelatedObject.decoder()),
+          Decoder.ofString(StandardCharsets.UTF_8),
+          Decoder.ofString(StandardCharsets.UTF_8),
+          Decoder.ofLong().withByteOrder(ByteOrder.BIG_ENDIAN),
+          Checksum.decoder(),
+          Checksum.decoder());
+
+  public static Decoder<Commit> decoder() {
+    return DECODER;
+  }
+}