diff --git a/src/components/nostr/kinds/BadgeDefinitionDetailRenderer.tsx b/src/components/nostr/kinds/BadgeDefinitionDetailRenderer.tsx
new file mode 100644
index 0000000..2be0d45
--- /dev/null
+++ b/src/components/nostr/kinds/BadgeDefinitionDetailRenderer.tsx
@@ -0,0 +1,226 @@
+import { NostrEvent } from "@/types/nostr";
+import {
+  getBadgeIdentifier,
+  getBadgeName,
+  getBadgeDescription,
+  getBadgeImage,
+  getBadgeThumbnails,
+} from "@/lib/nip58-helpers";
+import { UserName } from "../UserName";
+import { Award } from "lucide-react";
+import { useMemo } from "react";
+import { useLiveTimeline } from "@/hooks/useLiveTimeline";
+import { getSeenRelays } from "applesauce-core/helpers/relays";
+import { relayListCache } from "@/services/relay-list-cache";
+
+interface BadgeDefinitionDetailRendererProps {
+  event: NostrEvent;
+}
+
+/**
+ * Image variant display component
+ */
+function ImageVariant({
+  url,
+  dimensions,
+  label,
+}: {
+  url: string;
+  dimensions?: string;
+  label: string;
+}) {
+  return (
+    <div className="flex flex-col gap-2">
+      <div className="flex items-center justify-between">
+        <span className="text-sm font-medium text-muted-foreground">
+          {label}
+        </span>
+        {dimensions && (
+          <code className="text-xs text-muted-foreground">{dimensions}</code>
+        )}
+      </div>
+      <img
+        src={url}
+        alt={label}
+        className="w-full max-w-[200px] rounded-lg object-cover"
+        loading="lazy"
+      />
+    </div>
+  );
+}
+
+/**
+ * Detail renderer for Kind 30009 - Badge Definition (NIP-58)
+ * Shows comprehensive badge information including all image variants
+ */
+export function BadgeDefinitionDetailRenderer({
+  event,
+}: BadgeDefinitionDetailRendererProps) {
+  const identifier = getBadgeIdentifier(event);
+  const name = getBadgeName(event);
+  const description = getBadgeDescription(event);
+  const image = getBadgeImage(event);
+  const thumbnails = getBadgeThumbnails(event);
+
+  // Use name if available, fallback to identifier
+  const displayTitle = name || identifier || "Badge";
+
+  // Build relay list for fetching badge awards (kind 8)
+  const relays = useMemo(() => {
+    const relaySet = new Set<string>();
+
+    // Add seen relays from the badge definition event
+    const seenRelays = getSeenRelays(event);
+    if (seenRelays) {
+      for (const relay of seenRelays) {
+        relaySet.add(relay);
+      }
+    }
+
+    // Add issuer's outbox relays
+    const outboxRelays = relayListCache.getOutboxRelaysSync(event.pubkey);
+    if (outboxRelays) {
+      for (const relay of outboxRelays.slice(0, 3)) {
+        relaySet.add(relay);
+      }
+    }
+
+    return Array.from(relaySet);
+  }, [event]);
+
+  // Query for awards (kind 8) that reference this badge definition
+  const awardsFilter = useMemo(() => {
+    if (!identifier) {
+      return { kinds: [8], ids: [] }; // No match if no identifier
+    }
+    return {
+      kinds: [8],
+      "#a": [`30009:${event.pubkey}:${identifier}`],
+    };
+  }, [event.pubkey, identifier]);
+
+  // Fetch awards from relays
+  const { events: awards } = useLiveTimeline(
+    `badge-awards-${event.id}`,
+    awardsFilter,
+    relays,
+    { limit: 100 },
+  );
+
+  // Count unique recipients
+  const uniqueRecipients = useMemo(() => {
+    if (!awards || awards.length === 0) return 0;
+    const recipients = new Set<string>();
+    for (const award of awards) {
+      const pTags = award.tags.filter((tag) => tag[0] === "p" && tag[1]);
+      for (const pTag of pTags) {
+        recipients.add(pTag[1]);
+      }
+    }
+    return recipients.size;
+  }, [awards]);
+
+  return (
+    <div className="flex flex-col gap-6 p-6 max-w-4xl mx-auto">
+      {/* Header Section */}
+      <div className="flex gap-4">
+        {/* Badge Image */}
+        {image ? (
+          <img
+            src={image.url}
+            alt={displayTitle}
+            className="size-32 rounded-lg object-cover flex-shrink-0"
+            loading="lazy"
+          />
+        ) : (
+          <div className="size-32 rounded-lg bg-muted flex items-center justify-center flex-shrink-0">
+            <Award className="size-16 text-muted-foreground" />
+          </div>
+        )}
+
+        {/* Badge Title & Description */}
+        <div className="flex flex-col gap-2 flex-1 min-w-0">
+          <h1 className="text-3xl font-bold">{displayTitle}</h1>
+          {description && (
+            <p className="text-muted-foreground text-base">{description}</p>
+          )}
+        </div>
+      </div>
+
+      {/* Metadata Grid */}
+      <div className="grid grid-cols-2 gap-4 text-sm">
+        {/* Issuer */}
+        <div className="flex flex-col gap-1">
+          <h3 className="text-muted-foreground">Issued By</h3>
+          <UserName pubkey={event.pubkey} />
+        </div>
+
+        {/* Identifier */}
+        {identifier && (
+          <div className="flex flex-col gap-1">
+            <h3 className="text-muted-foreground">Badge ID</h3>
+            <code className="font-mono text-sm truncate" title={identifier}>
+              {identifier}
+            </code>
+          </div>
+        )}
+
+        {/* Awards Count */}
+        {awards && awards.length > 0 && (
+          <div className="flex flex-col gap-1">
+            <h3 className="text-muted-foreground">Times Awarded</h3>
+            <span className="text-sm">
+              {awards.length} award{awards.length !== 1 ? "s" : ""}
+            </span>
+          </div>
+        )}
+
+        {/* Recipients Count */}
+        {uniqueRecipients > 0 && (
+          <div className="flex flex-col gap-1">
+            <h3 className="text-muted-foreground">Recipients</h3>
+            <span className="text-sm">
+              {uniqueRecipients} user{uniqueRecipients !== 1 ? "s" : ""}
+            </span>
+          </div>
+        )}
+      </div>
+
+      {/* Image Variants Section */}
+      {(image || thumbnails.length > 0) && (
+        <div className="flex flex-col gap-3">
+          <h2 className="text-xl font-semibold">Image Variants</h2>
+          <div className="grid grid-cols-2 md:grid-cols-3 gap-4">
+            {image && (
+              <ImageVariant
+                url={image.url}
+                dimensions={image.dimensions}
+                label="Main Image"
+              />
+            )}
+            {thumbnails.map((thumb, idx) => (
+              <ImageVariant
+                key={idx}
+                url={thumb.url}
+                dimensions={thumb.dimensions}
+                label={`Thumbnail ${idx + 1}`}
+              />
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Award Address for Reference */}
+      {identifier && (
+        <div className="flex flex-col gap-2 p-4 bg-muted/30 rounded-lg">
+          <h3 className="text-sm font-medium text-muted-foreground">
+            Badge Address (for awarding)
+          </h3>
+          <code className="text-xs font-mono break-all">
+            30009:{event.pubkey}:{identifier}
+          </code>
+        </div>
+      )}
+    </div>
+  );
+}
diff --git a/src/components/nostr/kinds/BadgeDefinitionRenderer.tsx b/src/components/nostr/kinds/BadgeDefinitionRenderer.tsx
new file mode 100644
index 0000000..8dcec5e
--- /dev/null
+++ b/src/components/nostr/kinds/BadgeDefinitionRenderer.tsx
@@ -0,0 +1,68 @@
+import {
+  BaseEventContainer,
+  BaseEventProps,
+  ClickableEventTitle,
+} from "./BaseEventRenderer";
+import {
+  getBadgeIdentifier,
+  getBadgeName,
+  getBadgeDescription,
+  getBadgeImageUrl,
+} from "@/lib/nip58-helpers";
+import { Award } from "lucide-react";
+
+/**
+ * Renderer for Kind 30009 - Badge Definition (NIP-58)
+ * Clean feed view with badge image, name, and description
+ */
+export function BadgeDefinitionRenderer({ event }: BaseEventProps) {
+  const identifier = getBadgeIdentifier(event);
+  const name = getBadgeName(event);
+  const description = getBadgeDescription(event);
+  const imageUrl = getBadgeImageUrl(event);
+
+  // Use name if available, fallback to identifier
+  const displayTitle = name || identifier || "Badge";
+
+  return (
+    <BaseEventContainer event={event}>
+      <div className="flex gap-3">
+        {/* Badge Image */}
+        {imageUrl ? (
+          <img
+            src={imageUrl}
+            alt={displayTitle}
+            className="size-16 rounded-lg object-cover flex-shrink-0"
+            loading="lazy"
+          />
+        ) : (
+          <div className="size-16 rounded-lg bg-muted flex items-center justify-center flex-shrink-0">
+            <Award className="size-8 text-muted-foreground" />
+          </div>
+        )}
+
+        {/* Badge Info */}
+        <div className="flex flex-col gap-1 flex-1 min-w-0">
+          <ClickableEventTitle
+            event={event}
+            className="text-base font-semibold text-foreground"
+          >
+            {displayTitle}
+          </ClickableEventTitle>
+
+          {description && (
+            <p className="text-sm text-muted-foreground line-clamp-2">
+              {description}
+            </p>
+          )}
+
+          {identifier && (
+            <code className="text-xs text-muted-foreground font-mono truncate">
+              {identifier}
+            </code>
+          )}
+        </div>
+      </div>
+    </BaseEventContainer>
+  );
+}
diff --git a/src/components/nostr/kinds/index.tsx b/src/components/nostr/kinds/index.tsx
index 59b4b05..7cd07ca 100644
--- a/src/components/nostr/kinds/index.tsx
+++ b/src/components/nostr/kinds/index.tsx
@@ -142,6 +142,8 @@ import { NostrEvent } from "@/types/nostr";
 import { BaseEventContainer, type BaseEventProps } from "./BaseEventRenderer";
 import { P2pOrderRenderer } from "./P2pOrderRenderer";
 import { P2pOrderDetailRenderer } from "./P2pOrderDetailRenderer";
+import { BadgeDefinitionRenderer } from "./BadgeDefinitionRenderer";
+import { BadgeDefinitionDetailRenderer } from "./BadgeDefinitionDetailRenderer";
 
 /**
  * Registry of kind-specific renderers
@@ -200,6 +202,7 @@ const kindRenderers: Record<number, React.ComponentType<BaseEventProps>> = {
   30005: VideoCurationSetRenderer, // Video Curation Sets (NIP-51)
   30006: PictureCurationSetRenderer, // Picture Curation Sets (NIP-51)
   30007: KindMuteSetRenderer, // Kind Mute Sets (NIP-51)
+  30009: BadgeDefinitionRenderer, // Badge Definition (NIP-58)
   30015: InterestSetRenderer, // Interest Sets (NIP-51)
   30023: Kind30023Renderer, // Long-form Article
   30030: EmojiSetRenderer, // Emoji Sets (NIP-30)
@@ -293,6 +296,7 @@ const detailRenderers: Record<
   30005: VideoCurationSetDetailRenderer, // Video Curation Sets Detail (NIP-51)
   30006: PictureCurationSetDetailRenderer, // Picture Curation Sets Detail (NIP-51)
   30007: KindMuteSetDetailRenderer, // Kind Mute Sets Detail (NIP-51)
+  30009: BadgeDefinitionDetailRenderer, // Badge Definition Detail (NIP-58)
   30015: InterestSetDetailRenderer, // Interest Sets Detail (NIP-51)
   30023: Kind30023DetailRenderer, // Long-form Article Detail
   30030: EmojiSetDetailRenderer, // Emoji Sets Detail (NIP-30)
diff --git a/src/lib/nip58-helpers.ts b/src/lib/nip58-helpers.ts
new file mode 100644
index 0000000..f89b5d7
--- /dev/null
+++ b/src/lib/nip58-helpers.ts
@@ -0,0 +1,95 @@
+import { getTagValue } from "applesauce-core/helpers";
+import { getTagValues } from "./nostr-utils";
+import type { NostrEvent } from "nostr-tools";
+
+/**
+ * NIP-58 Badge Helpers
+ * These helpers extract badge-related metadata from badge events.
+ * They wrap getTagValue which caches results internally, so no need for useMemo.
+ */
+
+/**
+ * Get the unique identifier for a badge definition (d tag)
+ */
+export function getBadgeIdentifier(event: NostrEvent): string | undefined {
+  return getTagValue(event, "d");
+}
+
+/**
+ * Get the display name for a badge
+ */
+export function getBadgeName(event: NostrEvent): string | undefined {
+  return getTagValue(event, "name");
+}
+
+/**
+ * Get the description explaining the badge meaning or issuance criteria
+ */
+export function getBadgeDescription(event: NostrEvent): string | undefined {
+  return getTagValue(event, "description");
+}
+
+/**
+ * Get the badge image URL and optional dimensions
+ * @returns Object with url and optional dimensions (e.g., "1024x1024")
+ */
+export function getBadgeImage(event: NostrEvent): {
+  url: string;
+  dimensions?: string;
+} | null {
+  const imageTag = event.tags.find((tag) => tag[0] === "image" && tag[1]);
+  if (!imageTag) return null;
+
+  return {
+    url: imageTag[1],
+    dimensions: imageTag[2],
+  };
+}
+
+/**
+ * Get all thumbnail variants with dimensions
+ * @returns Array of thumbnails with url and optional dimensions
+ */
+export function getBadgeThumbnails(event: NostrEvent): Array<{
+  url: string;
+  dimensions?: string;
+}> {
+  return event.tags
+    .filter((tag) => tag[0] === "thumb" && tag[1])
+    .map((tag) => ({
+      url: tag[1],
+      dimensions: tag[2],
+    }));
+}
+
+/**
+ * Get the best badge image URL to display based on available variants
+ * Prefers image over thumbnails
+ */
+export function getBadgeImageUrl(event: NostrEvent): string | null {
+  const image = getBadgeImage(event);
+  if (image) return image.url;
+
+  const thumbnails = getBadgeThumbnails(event);
+  if (thumbnails.length > 0) return thumbnails[0].url;
+
+  return null;
+}
+
+/**
+ * Get all pubkeys awarded this badge (from kind 8 award events)
+ * Note: This should be called on award events (kind 8), not badge definitions
+ */
+export function getAwardedPubkeys(awardEvent: NostrEvent): string[] {
+  return getTagValues(awardEvent, "p");
+}
+
+/**
+ * Get the badge definition address referenced by an award event (kind 8)
+ * @returns The "a" tag value (e.g., "30009:pubkey:identifier")
+ */
+export function getAwardBadgeAddress(
+  awardEvent: NostrEvent,
+): string | undefined {
+  return getTagValue(awardEvent, "a");
+}