diff --git a/.changeset/smart-humans-cover.md b/.changeset/smart-humans-cover.md
new file mode 100644
index 000000000..4408e0a9c
--- /dev/null
+++ b/.changeset/smart-humans-cover.md
@@ -0,0 +1,5 @@
+---
+'mermaid': patch
+---
+
+fix: Update flowchart direction TD's behavior to be the same as TB
diff --git a/packages/mermaid/src/diagrams/flowchart/flowDb.ts b/packages/mermaid/src/diagrams/flowchart/flowDb.ts
index 65f8c4a05..303ad0e66 100644
--- a/packages/mermaid/src/diagrams/flowchart/flowDb.ts
+++ b/packages/mermaid/src/diagrams/flowchart/flowDb.ts
@@ -403,7 +403,8 @@ You have to call mermaid.initialize.`
    *
    */
   public setDirection(dir: string) {
-    this.direction = dir;
+    this.direction = dir.trim();
+
     if (/.*</.exec(this.direction)) {
       this.direction = 'RL';
     }