diff --git a/src/Documentation/root.ts b/src/Documentation/root.ts
index 59398ad76..3847e6981 100644
--- a/src/Documentation/root.ts
+++ b/src/Documentation/root.ts
@@ -31,7 +31,7 @@ export const getPage = (title: string): string => {
   return resolvePage(title).pageContent;
 };
 
-export const DocumentationPopUpEvents = new EventEmitter<[string | undefined]>();
+export const DocumentationPopUpEvents = new EventEmitter<[string]>();
 
 export function openDocumentationPopUp(path: string): void {
   DocumentationPopUpEvents.emit(path);
diff --git a/src/Documentation/ui/DocumentationPopUp.tsx b/src/Documentation/ui/DocumentationPopUp.tsx
index 4764a0e75..27d55e8ee 100644
--- a/src/Documentation/ui/DocumentationPopUp.tsx
+++ b/src/Documentation/ui/DocumentationPopUp.tsx
@@ -1,8 +1,8 @@
 import React, { useEffect, useRef, useState } from "react";
 import { Modal } from "../../ui/React/Modal";
-import { defaultNsApiPage, Navigator, openDocExternally } from "../../ui/React/Documentation";
+import { convertNavigatorHref, Navigator, openDocExternally } from "../../ui/React/Documentation";
 import { MD } from "../../ui/MD/MD";
-import { asFilePath, type FilePath, isFilePath, resolveFilePath } from "../../Paths/FilePath";
+import { asFilePath, type FilePath } from "../../Paths/FilePath";
 import { DocumentationPopUpEvents } from "../root";
 
 export function DocumentationPopUp({ hidden }: { hidden: boolean }) {
@@ -11,8 +11,8 @@ export function DocumentationPopUp({ hidden }: { hidden: boolean }) {
 
   useEffect(
     () =>
-      DocumentationPopUpEvents.subscribe((path?: string) => {
-        setPath(path ? asFilePath(path) : undefined);
+      DocumentationPopUpEvents.subscribe((path: string) => {
+        setPath(asFilePath(path));
       }),
     [],
   );
@@ -24,39 +24,30 @@ export function DocumentationPopUp({ hidden }: { hidden: boolean }) {
     modalWrapperRef.current.scrollTo({ top: 0, behavior: "instant" });
   });
 
-  const navigator = {
-    navigate(href: string, openExternally: boolean) {
-      /**
-       * This function is used for navigating inside the documentation popup.
-       *
-       * Href can be:
-       * - Internal NS docs. The "markdown" folder does not have any subfolders. All files are at the top-level. "Href"
-       * is always "./<filename>". E.g., "./bitburner.ns.md".
-       * - HTTP URL (e.g., ns.printf has a link to https://github.com/alexei/sprintf.js).
-       */
-      let path;
-      if (href.startsWith("https://") || href.startsWith("http://")) {
-        openExternally = true;
-        path = href;
-      } else {
-        path = resolveFilePath(href, defaultNsApiPage);
-      }
-      if (!path) {
-        console.error(`Bad path ${href} while navigating docs.`);
-        return;
-      }
-      if (openExternally) {
-        openDocExternally(path);
-        return;
-      }
-      if (isFilePath(path)) {
-        setPath(path);
-      }
-    },
-  };
   if (!path) {
     return <></>;
   }
+
+  const navigator = {
+    /**
+     * This function is used for navigating inside the documentation popup.
+     */
+    navigate(href: string, openExternally: boolean) {
+      if (!path) {
+        return;
+      }
+      const { path: newPath, forceOpenExternally } = convertNavigatorHref(href, path);
+      if (!newPath) {
+        console.error(`Bad path ${href} while navigating docs.`);
+        return;
+      }
+      if (openExternally || forceOpenExternally) {
+        openDocExternally(newPath);
+        return;
+      }
+      setPath(newPath);
+    },
+  };
   return (
     <Modal
       open={!hidden}
diff --git a/src/Documentation/ui/DocumentationRoot.tsx b/src/Documentation/ui/DocumentationRoot.tsx
index 2743a1329..af994afb3 100644
--- a/src/Documentation/ui/DocumentationRoot.tsx
+++ b/src/Documentation/ui/DocumentationRoot.tsx
@@ -9,9 +9,9 @@ import {
   windowTopPositionOfPages,
   useHistory,
   openDocExternally,
-  prefixOfHttpUrlOfNsDocs,
+  convertNavigatorHref,
 } from "../../ui/React/Documentation";
-import { asFilePath, isFilePath, resolveFilePath } from "../../Paths/FilePath";
+import { asFilePath } from "../../Paths/FilePath";
 import { Settings } from "../../Settings/Settings";
 import { Router } from "../../ui/GameRoot";
 import { Page } from "../../ui/Router";
@@ -21,48 +21,20 @@ export function DocumentationRoot({ docPage }: { docPage?: string }): React.Reac
   const history = useHistory();
   const [deepLink, setDeepLink] = useState(docPage);
   const navigator = {
+    /**
+     * This function is used for navigating inside the documentation tab.
+     */
     navigate(href: string, openExternally: boolean) {
-      let path;
-      /**
-       * Href can be:
-       * - Internal NS docs: nsDoc/bitburner.ns.md
-       * - Internal non-NS docs: help/getting_started.md
-       * - HTTP URL:
-       *   - Point to NS docs. Some non-NS docs pages include links to NS docs. For example: basic/scripts.md has a
-       * link to https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/bitburner.ns.flags.md. In
-       * these cases, the link always points to a file at https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/
-       *   - Point to other places.
-       */
-      if (href.startsWith("nsDoc/")) {
-        // Internal NS docs
-        path = asFilePath(href);
-      } else if (href.startsWith("https://") || href.startsWith("http://")) {
-        /**
-         * HTTP URL pointing to NS docs.
-         * Convert https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/page.md to nsDoc/page.md
-         */
-        if (href.startsWith(prefixOfHttpUrlOfNsDocs)) {
-          path = asFilePath(`nsDoc/${href.replace(prefixOfHttpUrlOfNsDocs, "")}`);
-        } else {
-          // HTTP URL pointing to other places.
-          openExternally = true;
-          path = href;
-        }
-      } else {
-        // Internal non-NS docs
-        path = resolveFilePath("./" + href, history.page);
-      }
+      const { path, forceOpenExternally } = convertNavigatorHref(href, history.page);
       if (!path) {
         console.error(`Bad path ${href} from ${history.page} while navigating docs.`);
         return;
       }
-      if (openExternally) {
+      if (openExternally || forceOpenExternally) {
         openDocExternally(path);
         return;
       }
-      if (isFilePath(path)) {
-        history.push(path);
-      }
+      history.push(path);
     },
   };
 
diff --git a/src/ui/React/Documentation.tsx b/src/ui/React/Documentation.tsx
index 07a98cf65..8f7d00702 100644
--- a/src/ui/React/Documentation.tsx
+++ b/src/ui/React/Documentation.tsx
@@ -1,5 +1,5 @@
 import React, { useContext, useState } from "react";
-import { type FilePath, asFilePath } from "../../Paths/FilePath";
+import { type FilePath, asFilePath, resolveFilePath } from "../../Paths/FilePath";
 import { CONSTANTS } from "../../Constants";
 import { resolvePage } from "../../Documentation/root";
 
@@ -21,7 +21,7 @@ interface History {
   home(): void;
 }
 
-const defaultPage = asFilePath("index.md");
+export const defaultPage = asFilePath("index.md");
 export const defaultNsApiPage = asFilePath("nsDoc/bitburner.ns.md");
 /**
  * If we move or rename "bitburner.ns.md", we must update this constant, "defaultNsApiPage", "openDocExternally", and
@@ -31,6 +31,8 @@ export const externalUrlOfNsApiPage =
   "https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/bitburner.ns.md";
 export const prefixOfHttpUrlOfNsDocs = "https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/";
 
+const prefixOfRelativeUrlOfNSDoc = "../../../../markdown/bitburner.";
+
 const HistoryContext = React.createContext<History>({
   page: defaultPage,
   pages: [],
@@ -92,7 +94,7 @@ export const HistoryProvider = (props: React.PropsWithChildren<object>): React.R
   return <Provider value={history}>{props.children}</Provider>;
 };
 
-export function openDocExternally(path: string) {
+export function openDocExternally(path: string): void {
   const ver = CONSTANTS.isDevBranch ? "dev" : "stable";
   let url;
   if (path.startsWith("http://") || path.startsWith("https://")) {
@@ -111,3 +113,55 @@ export function openDocExternally(path: string) {
   }
   window.open(url, "_newtab");
 }
+
+/**
+ * Href can be:
+ * - Relative URL from non-NS docs pointing to markdown folder: Open "../../../../markdown/bitburner.ns.md" from "index.md"
+ * - Relative URL from NS docs to other NS docs (e.g., click the links in NS docs viewer): Open "./bitburner.ns.cloud.md" from "nsDoc/bitburner.ns.md"
+ * - Internal NS docs (e.g., choose a dropdown option in DocumentationAutocomplete): nsDoc/bitburner.ns.md
+ * - Internal non-NS docs: help/getting_started.md
+ * - HTTP URL:
+ *   - Point to NS docs. Some non-NS docs pages include links to NS docs. For example: basic/scripts.md has a
+ * link to https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/bitburner.ns.flags.md. In
+ * these cases, the link always points to a file at https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/
+ *   - Point to other places.
+ */
+export function convertNavigatorHref(
+  href: string,
+  currentPage: FilePath,
+): { path: FilePath | null; forceOpenExternally: false } | { path: string; forceOpenExternally: true } {
+  let path;
+  if (href.includes(prefixOfRelativeUrlOfNSDoc)) {
+    // Relative URL from non-NS docs pointing to markdown folder
+    path = asFilePath(
+      // Convert "../../../../markdown/bitburner.foo.md" and "deeper" URLs (i.e., having more "../") to "nsDoc/bitburner.foo.md"
+      href.replace(
+        href.substring(0, href.indexOf(prefixOfRelativeUrlOfNSDoc) + prefixOfRelativeUrlOfNSDoc.length),
+        "nsDoc/bitburner.",
+      ),
+    );
+  } else if (/^\.\/bitburner\.[^/]*\.md$/.test(href)) {
+    // Relative URL from NS docs to other NS docs. The URL is always ./bitburner.foo.md
+    // - Start with "./bitburner."
+    // - End with ".md"
+    // - Never have "/" between "./bitburner." and ".md"
+    path = resolveFilePath(href, defaultNsApiPage);
+  } else if (href.startsWith("nsDoc/")) {
+    // Internal NS docs
+    path = asFilePath(href);
+  } else if (href.startsWith("https://") || href.startsWith("http://")) {
+    // TODO: Remove this case after converting all these links to relative links.
+    // HTTP URL pointing to NS docs.
+    // Convert https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/bitburner.foo.md to nsDoc/bitburner.foo.md
+    if (href.startsWith(prefixOfHttpUrlOfNsDocs)) {
+      path = asFilePath(`nsDoc/${href.replace(prefixOfHttpUrlOfNsDocs, "")}`);
+    } else {
+      // HTTP URL pointing to other places.
+      return { path: href, forceOpenExternally: true };
+    }
+  } else {
+    // Internal non-NS docs
+    path = resolveFilePath("./" + href, currentPage);
+  }
+  return { path, forceOpenExternally: false };
+}
diff --git a/test/jest/ui/DocumentationNavigator.test.ts b/test/jest/ui/DocumentationNavigator.test.ts
new file mode 100644
index 000000000..735709625
--- /dev/null
+++ b/test/jest/ui/DocumentationNavigator.test.ts
@@ -0,0 +1,81 @@
+import { asFilePath } from "../../../src/Paths/FilePath";
+import { convertNavigatorHref, defaultNsApiPage, defaultPage } from "../../../src/ui/React/Documentation";
+
+describe("convertNavigatorHref", () => {
+  describe("Valid href", () => {
+    test("Relative URL from non-NS docs pointing to markdown folder 1", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref("../../../../markdown/bitburner.ns.md", defaultPage);
+      expect(path).toStrictEqual("nsDoc/bitburner.ns.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+    test("Relative URL from non-NS docs pointing to markdown folder 2", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref(
+        "../../../../../markdown/bitburner.ns.flags.md",
+        asFilePath("basic/scripts.md"),
+      );
+      expect(path).toStrictEqual("nsDoc/bitburner.ns.flags.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+
+    test("Relative URL from NS docs to other NS docs", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref("./bitburner.ns.cloud.md", defaultNsApiPage);
+      expect(path).toStrictEqual("nsDoc/bitburner.ns.cloud.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+
+    test("Internal NS docs 1", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref("help/getting_started.md", defaultPage);
+      expect(path).toStrictEqual("help/getting_started.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+    test("Internal NS docs 2", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref(
+        "../basic/scripts.md",
+        asFilePath("help/getting_started.md"),
+      );
+      expect(path).toStrictEqual("basic/scripts.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+    test("Internal NS docs 3", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref("./faq.md", asFilePath("help/getting_started.md"));
+      expect(path).toStrictEqual("help/faq.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+    test("Internal NS docs 4", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref("faq.md", asFilePath("help/getting_started.md"));
+      expect(path).toStrictEqual("help/faq.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+
+    test("HTTP/HTTPS URL - Point to NS docs", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref(
+        "https://github.com/bitburner-official/bitburner-src/blob/stable/markdown/bitburner.ns.md",
+        defaultPage,
+      );
+      expect(path).toStrictEqual("nsDoc/bitburner.ns.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+    test("HTTP/HTTPS URL - Point to other places", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref("https://bitburner-official.github.io", defaultPage);
+      expect(path).toStrictEqual("https://bitburner-official.github.io");
+      expect(forceOpenExternally).toStrictEqual(true);
+    });
+  });
+
+  describe("Invalid href", () => {
+    test("Relative URL from non-NS docs not pointing to markdown folder", () => {
+      const { path, forceOpenExternally } = convertNavigatorHref("../../../markdown/bitburner.ns.md", defaultPage);
+      expect(path).toStrictEqual(null);
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+
+    test("Relative URL from NS docs to other NS docs", () => {
+      // The path is always "./bitburner.foo.md". It never starts with "../".
+      const { path, forceOpenExternally } = convertNavigatorHref("../bitburner.ns.cloud.md", defaultNsApiPage);
+      // This is an invalid path. Technically, it's a valid file path, but there is no doc file with this path. The path
+      // of NS docs is always prefixed with "nsDoc/".
+      expect(path).toStrictEqual("bitburner.ns.cloud.md");
+      expect(forceOpenExternally).toStrictEqual(false);
+    });
+  });
+});