diff --git a/js/utils/videoTags.js b/js/utils/videoTags.js
new file mode 100644
index 00000000..0a7188d3
--- /dev/null
+++ b/js/utils/videoTags.js
@@ -0,0 +1,136 @@
+// js/utils/videoTags.js
+
+/**
+ * @module utils/videoTags
+ * @description Helpers for collecting and formatting normalized video tags from
+ *               various metadata sources.
+ */
+
+const HASH_PREFIX_PATTERN = /^#+/;
+
+function isObject(value) {
+  return Boolean(value) && typeof value === "object";
+}
+
+function asIterableStrings(value) {
+  if (Array.isArray(value)) {
+    return value;
+  }
+  if (typeof value === "string") {
+    return [value];
+  }
+  return [];
+}
+
+function normalizeTagValue(rawValue) {
+  if (typeof rawValue !== "string") {
+    return "";
+  }
+
+  const trimmed = rawValue.trim();
+  if (!trimmed) {
+    return "";
+  }
+
+  const withoutHashes = trimmed.replace(HASH_PREFIX_PATTERN, "").trim();
+
+  return withoutHashes;
+}
+
+/**
+ * Prefix a tag with `#` for display purposes, ensuring a single leading hash.
+ *
+ * @param {string} tag - The normalized tag to format.
+ * @returns {string} The tag prefixed with `#` when a tag exists, otherwise an
+ *                   empty string.
+ */
+export function formatTagDisplay(tag) {
+  if (typeof tag !== "string") {
+    return "";
+  }
+
+  const trimmed = tag.trim();
+  if (!trimmed) {
+    return "";
+  }
+
+  return `#${trimmed.replace(HASH_PREFIX_PATTERN, "").trim()}`;
+}
+
+/**
+ * Collect normalized hashtags from a video object, deduping across NIP-71
+ * metadata and traditional Nostr tag arrays. Results are sorted alphabetically
+ * in a case-insensitive manner while preserving the first-seen casing.
+ *
+ * @param {object} video - Video metadata that may contain NIP-71 structured
+ *                         fields or Nostr tag arrays.
+ * @param {object} [options]
+ * @param {boolean} [options.includeHashes=false] - When true, prefix `#` on the
+ *                                                  returned tag strings.
+ * @returns {string[]} Sorted list of unique tag strings.
+ */
+export function collectVideoTags(video, { includeHashes = false } = {}) {
+  if (!isObject(video)) {
+    return [];
+  }
+
+  const deduped = new Set();
+  const collected = [];
+
+  const pushTag = (rawValue) => {
+    const normalized = normalizeTagValue(rawValue);
+    if (!normalized) {
+      return;
+    }
+
+    const lower = normalized.toLowerCase();
+    if (deduped.has(lower)) {
+      return;
+    }
+
+    deduped.add(lower);
+    collected.push(normalized);
+  };
+
+  if (isObject(video.nip71)) {
+    const { hashtags, t } = video.nip71;
+    for (const candidate of asIterableStrings(hashtags)) {
+      pushTag(candidate);
+    }
+    for (const candidate of asIterableStrings(t)) {
+      pushTag(candidate);
+    }
+  }
+
+  if (Array.isArray(video.tags)) {
+    for (const tagTuple of video.tags) {
+      if (!Array.isArray(tagTuple) || tagTuple.length < 2) {
+        continue;
+      }
+
+      const [marker, value] = tagTuple;
+      if (typeof marker !== "string" || marker.toLowerCase() !== "t") {
+        continue;
+      }
+
+      pushTag(value);
+    }
+  }
+
+  collected.sort((a, b) => {
+    const lowerA = a.toLowerCase();
+    const lowerB = b.toLowerCase();
+    if (lowerA === lowerB) {
+      return a.localeCompare(b);
+    }
+    return lowerA.localeCompare(lowerB);
+  });
+
+  if (!includeHashes) {
+    return collected;
+  }
+
+  return collected.map((tag) => formatTagDisplay(tag));
+}
+
+export default collectVideoTags;
diff --git a/tests/utils/video-tags.test.mjs b/tests/utils/video-tags.test.mjs
new file mode 100644
index 00000000..e1053506
--- /dev/null
+++ b/tests/utils/video-tags.test.mjs
@@ -0,0 +1,54 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { collectVideoTags, formatTagDisplay } from "../../js/utils/videoTags.js";
+
+test("collectVideoTags dedupes across metadata sources and respects casing", () => {
+  const video = {
+    nip71: {
+      hashtags: ["#Tag", "Another"],
+      t: ["Third"],
+    },
+    tags: [
+      ["t", "tag"],
+      ["t", "ANOTHER"],
+      ["t", " #FOURTH "],
+      ["x", "ignored"],
+      ["t"],
+    ],
+  };
+
+  const tags = collectVideoTags(video);
+
+  assert.deepEqual(tags, ["Another", "FOURTH", "Tag", "Third"]);
+});
+
+test("collectVideoTags sorts case-insensitively and adds hashes when requested", () => {
+  const video = {
+    nip71: {
+      hashtags: ["beta", "Alpha"],
+    },
+    tags: [["t", "gamma"], ["t", "alpha"]],
+  };
+
+  const tags = collectVideoTags(video, { includeHashes: true });
+
+  assert.deepEqual(tags, ["#Alpha", "#beta", "#gamma"]);
+});
+
+test("collectVideoTags handles malformed inputs safely", () => {
+  assert.deepEqual(collectVideoTags(null), []);
+  assert.deepEqual(collectVideoTags(undefined), []);
+  assert.deepEqual(collectVideoTags(42), []);
+  assert.deepEqual(
+    collectVideoTags({ nip71: { hashtags: [null, "   "] }, tags: [["t"], ["t", null]] }),
+    [],
+  );
+});
+
+test("formatTagDisplay normalizes leading hashes", () => {
+  assert.equal(formatTagDisplay(" example"), "#example");
+  assert.equal(formatTagDisplay("##Example"), "#Example");
+  assert.equal(formatTagDisplay(""), "");
+  assert.equal(formatTagDisplay(null), "");
+});