diff --git a/src/pages/Admin/UserManagement/RolesTab.tsx b/src/pages/Admin/UserManagement/RolesTab.tsx
new file mode 100644
index 0000000..f7d10e4
--- /dev/null
+++ b/src/pages/Admin/UserManagement/RolesTab.tsx
@@ -0,0 +1,213 @@
+import { useState, useMemo } from 'react'
+import { Avatar } from '../../../design-system/primitives/Avatar/Avatar'
+import { Badge } from '../../../design-system/primitives/Badge/Badge'
+import { Button } from '../../../design-system/primitives/Button/Button'
+import { Input } from '../../../design-system/primitives/Input/Input'
+import { MonoText } from '../../../design-system/primitives/MonoText/MonoText'
+import { SectionHeader } from '../../../design-system/primitives/SectionHeader/SectionHeader'
+import { Tag } from '../../../design-system/primitives/Tag/Tag'
+import { ConfirmDialog } from '../../../design-system/composites/ConfirmDialog/ConfirmDialog'
+import { MOCK_ROLES, MOCK_GROUPS, MOCK_USERS, getEffectiveRoles, type MockRole } from './rbacMocks'
+import styles from './UserManagement.module.css'
+
+export function RolesTab() {
+  const [roles, setRoles] = useState(MOCK_ROLES)
+  const [search, setSearch] = useState('')
+  const [selectedId, setSelectedId] = useState<string | null>(null)
+  const [creating, setCreating] = useState(false)
+  const [deleteTarget, setDeleteTarget] = useState<MockRole | null>(null)
+
+  const [newName, setNewName] = useState('')
+  const [newDesc, setNewDesc] = useState('')
+
+  const filtered = useMemo(() => {
+    if (!search) return roles
+    const q = search.toLowerCase()
+    return roles.filter((r) =>
+      r.name.toLowerCase().includes(q) || r.description.toLowerCase().includes(q)
+    )
+  }, [roles, search])
+
+  const selected = roles.find((r) => r.id === selectedId) ?? null
+
+  function handleCreate() {
+    if (!newName.trim()) return
+    const newRole: MockRole = {
+      id: `role-${Date.now()}`,
+      name: newName.trim().toUpperCase(),
+      description: newDesc.trim(),
+      scope: 'custom',
+      system: false,
+    }
+    setRoles((prev) => [...prev, newRole])
+    setCreating(false)
+    setNewName(''); setNewDesc('')
+    setSelectedId(newRole.id)
+  }
+
+  function handleDelete() {
+    if (!deleteTarget) return
+    setRoles((prev) => prev.filter((r) => r.id !== deleteTarget.id))
+    if (selectedId === deleteTarget.id) setSelectedId(null)
+    setDeleteTarget(null)
+  }
+
+  // Role assignments
+  const assignedGroups = selected
+    ? MOCK_GROUPS.filter((g) => g.directRoles.includes(selected.name))
+    : []
+
+  const directUsers = selected
+    ? MOCK_USERS.filter((u) => u.directRoles.includes(selected.name))
+    : []
+
+  const effectivePrincipals = selected
+    ? MOCK_USERS.filter((u) => getEffectiveRoles(u).some((r) => r.role === selected.name))
+    : []
+
+  function getAssignmentCount(role: MockRole): number {
+    const groups = MOCK_GROUPS.filter((g) => g.directRoles.includes(role.name)).length
+    const users = MOCK_USERS.filter((u) => u.directRoles.includes(role.name)).length
+    return groups + users
+  }
+
+  return (
+    <>
+      <div className={styles.splitPane}>
+        <div className={styles.listPane}>
+          <div className={styles.listHeader}>
+            <Input
+              placeholder="Search roles..."
+              value={search}
+              onChange={(e) => setSearch(e.target.value)}
+              onClear={() => setSearch('')}
+              className={styles.listHeaderSearch}
+            />
+            <Button size="sm" variant="secondary" onClick={() => setCreating(true)}>
+              + Add role
+            </Button>
+          </div>
+
+          {creating && (
+            <div className={styles.createForm}>
+              <Input placeholder="Role name *" value={newName} onChange={(e) => setNewName(e.target.value)} />
+              <Input placeholder="Description" value={newDesc} onChange={(e) => setNewDesc(e.target.value)} />
+              <div className={styles.createFormActions}>
+                <Button size="sm" variant="ghost" onClick={() => setCreating(false)}>Cancel</Button>
+                <Button size="sm" variant="primary" onClick={handleCreate} disabled={!newName.trim()}>Create</Button>
+              </div>
+            </div>
+          )}
+
+          <div className={styles.entityList}>
+            {filtered.map((role) => (
+              <div
+                key={role.id}
+                className={`${styles.entityItem} ${selectedId === role.id ? styles.entityItemSelected : ''}`}
+                onClick={() => setSelectedId(role.id)}
+              >
+                <Avatar name={role.name} size="sm" />
+                <div className={styles.entityInfo}>
+                  <div className={styles.entityName}>
+                    {role.name}
+                    {role.system && <span title="System role"> 🔒</span>}
+                  </div>
+                  <div className={styles.entityMeta}>
+                    {role.description} · {getAssignmentCount(role)} assignments
+                  </div>
+                  <div className={styles.entityTags}>
+                    {MOCK_GROUPS.filter((g) => g.directRoles.includes(role.name))
+                      .map((g) => <Badge key={g.id} label={g.name} color="success" />)}
+                    {MOCK_USERS.filter((u) => u.directRoles.includes(role.name))
+                      .map((u) => <Badge key={u.id} label={u.username} color="auto" />)}
+                  </div>
+                </div>
+              </div>
+            ))}
+          </div>
+        </div>
+
+        <div className={styles.detailPane}>
+          {selected ? (
+            <>
+              <div className={styles.detailHeader}>
+                <Avatar name={selected.name} size="lg" />
+                <div className={styles.detailHeaderInfo}>
+                  <div className={styles.detailName}>{selected.name}</div>
+                  {selected.description && (
+                    <div className={styles.detailEmail}>{selected.description}</div>
+                  )}
+                </div>
+                {!selected.system && (
+                  <Button
+                    size="sm"
+                    variant="danger"
+                    onClick={() => setDeleteTarget(selected)}
+                  >
+                    Delete
+                  </Button>
+                )}
+              </div>
+
+              <div className={styles.metaGrid}>
+                <span className={styles.metaLabel}>ID</span>
+                <MonoText size="xs">{selected.id}</MonoText>
+                <span className={styles.metaLabel}>Scope</span>
+                <span className={styles.metaValue}>{selected.scope}</span>
+                {selected.system && (
+                  <>
+                    <span className={styles.metaLabel}>Type</span>
+                    <span className={styles.metaValue}>System role (read-only)</span>
+                  </>
+                )}
+              </div>
+
+              <SectionHeader>Assigned to groups</SectionHeader>
+              <div className={styles.sectionTags}>
+                {assignedGroups.map((g) => <Tag key={g.id} label={g.name} color="success" />)}
+                {assignedGroups.length === 0 && <span className={styles.inheritedNote}>(none)</span>}
+              </div>
+
+              <SectionHeader>Assigned to users (direct)</SectionHeader>
+              <div className={styles.sectionTags}>
+                {directUsers.map((u) => <Tag key={u.id} label={u.displayName} color="auto" />)}
+                {directUsers.length === 0 && <span className={styles.inheritedNote}>(none)</span>}
+              </div>
+
+              <SectionHeader>Effective principals</SectionHeader>
+              <div className={styles.sectionTags}>
+                {effectivePrincipals.map((u) => {
+                  const isDirect = u.directRoles.includes(selected.name)
+                  return (
+                    <Badge
+                      key={u.id}
+                      label={u.displayName}
+                      color="auto"
+                      variant={isDirect ? 'filled' : 'dashed'}
+                    />
+                  )
+                })}
+                {effectivePrincipals.length === 0 && <span className={styles.inheritedNote}>(none)</span>}
+              </div>
+              {effectivePrincipals.some((u) => !u.directRoles.includes(selected.name)) && (
+                <span className={styles.inheritedNote}>
+                  Dashed entries inherit this role through group membership
+                </span>
+              )}
+            </>
+          ) : (
+            <div className={styles.emptyDetail}>Select a role to view details</div>
+          )}
+        </div>
+      </div>
+
+      <ConfirmDialog
+        open={deleteTarget !== null}
+        onClose={() => setDeleteTarget(null)}
+        onConfirm={handleDelete}
+        message={`Delete role "${deleteTarget?.name}"? This cannot be undone.`}
+        confirmText={deleteTarget?.name ?? ''}
+      />
+    </>
+  )
+}