diff --git a/.changelog/35.txt b/.changelog/35.txt
new file mode 100644
index 0000000..3403f19
--- /dev/null
+++ b/.changelog/35.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+tfsdklog: Consolidated multiple invalid log level messages and added missing newline
+```
diff --git a/tfsdklog/sink.go b/tfsdklog/sink.go
index eeb8c8a..271039d 100644
--- a/tfsdklog/sink.go
+++ b/tfsdklog/sink.go
@@ -6,6 +6,7 @@ import (
 	"io"
 	"os"
 	"strings"
+	"sync"
 	"syscall"
 
 	"github.com/hashicorp/go-hclog"
@@ -53,6 +54,9 @@ const (
 // loggers.
 var ValidLevels = []string{"TRACE", "DEBUG", "INFO", "WARN", "ERROR", "OFF"}
 
+// Only show invalid log level message once across any number of level lookups.
+var invalidLogLevelMessage sync.Once
+
 func getSink(ctx context.Context) hclog.Logger {
 	logger := ctx.Value(logging.SinkKey)
 	if logger == nil {
@@ -120,8 +124,14 @@ func newSink(t testing.T) hclog.Logger {
 	} else if isValidLogLevel(envLevel) {
 		logLevel = hclog.LevelFromString(envLevel)
 	} else {
-		fmt.Fprintf(os.Stderr, "[WARN] Invalid log level: %q. Defaulting to level: OFF. Valid levels are: %+v",
-			envLevel, ValidLevels)
+		invalidLogLevelMessage.Do(func() {
+			fmt.Fprintf(
+				os.Stderr,
+				"[WARN] Invalid log level: %q. Defaulting to level: OFF. Valid levels are: %+v\n",
+				envLevel,
+				ValidLevels,
+			)
+		})
 	}
 
 	return hclog.New(&hclog.LoggerOptions{