diff --git a/modules/xatlas_unwrap/register_types.cpp b/modules/xatlas_unwrap/register_types.cpp
index 6f397fe2859..139df9c735e 100644
--- a/modules/xatlas_unwrap/register_types.cpp
+++ b/modules/xatlas_unwrap/register_types.cpp
@@ -120,6 +120,8 @@ bool xatlas_mesh_lightmap_unwrap_callback(float p_texel_size, const float *p_ver
 		xatlas::ChartOptions chart_options;
 		chart_options.fixWinding = true;
 
+		ERR_FAIL_COND_V_MSG(p_texel_size <= 0.0f, false, "Texel size must be greater than 0.");
+
 		xatlas::PackOptions pack_options;
 		pack_options.padding = 1;
 		pack_options.maxChartSize = 4094; // Lightmap atlassing needs 2 for padding between meshes, so 4096-2
diff --git a/scene/resources/mesh.cpp b/scene/resources/mesh.cpp
index 441e84ecccc..6b44b05e02f 100644
--- a/scene/resources/mesh.cpp
+++ b/scene/resources/mesh.cpp
@@ -1684,6 +1684,7 @@ Error ArrayMesh::lightmap_unwrap(const Transform3D &p_base_transform, float p_te
 Error ArrayMesh::lightmap_unwrap_cached(const Transform3D &p_base_transform, float p_texel_size, const Vector<uint8_t> &p_src_cache, Vector<uint8_t> &r_dst_cache, bool p_generate_cache) {
 	ERR_FAIL_COND_V(!array_mesh_lightmap_unwrap_callback, ERR_UNCONFIGURED);
 	ERR_FAIL_COND_V_MSG(blend_shapes.size() != 0, ERR_UNAVAILABLE, "Can't unwrap mesh with blend shapes.");
+	ERR_FAIL_COND_V_MSG(p_texel_size <= 0.0f, ERR_PARAMETER_RANGE_ERROR, "Texel size must be greater than 0.");
 
 	LocalVector<float> vertices;
 	LocalVector<float> normals;