diff --git a/R/PackageInheritanceReporter.R b/R/PackageInheritanceReporter.R
index 5246045d..f1c96e98 100644
--- a/R/PackageInheritanceReporter.R
+++ b/R/PackageInheritanceReporter.R
@@ -136,7 +136,7 @@ InheritanceReporter <- R6::R6Class(
 
                 if (nrow(nodeDT) == 0) {
                     msg <- sprintf(
-                        'No Reference Class or R6 Class definitions found in package %s'
+                        'No S4, Reference, or R6 class definitions found in package %s'
                         , self$pkg_name
                     )
                     log_warn(msg)
diff --git a/tests/testthat/test-InheritanceReporter.R b/tests/testthat/test-InheritanceReporter.R
index 310b0780..0f792375 100644
--- a/tests/testthat/test-InheritanceReporter.R
+++ b/tests/testthat/test-InheritanceReporter.R
@@ -145,7 +145,7 @@ test_that("InheritanceReporter should give warning for packages with no classes"
         reporter <- InheritanceReporter$new()
         reporter$set_package("baseballstats")
         reporter$edges
-    }, regexp = "No Reference Class or R6 Class definitions found")
+    }, regexp = "No S4, Reference, or R6 class definitions found")
 })
 
 ##### TEST TEAR DOWN #####