diff --git a/apps/blade/src/app/_components/issues/create-edit-dialog.tsx b/apps/blade/src/app/_components/issues/create-edit-dialog.tsx
index 68fc7b3e3..4586af220 100644
--- a/apps/blade/src/app/_components/issues/create-edit-dialog.tsx
+++ b/apps/blade/src/app/_components/issues/create-edit-dialog.tsx
@@ -190,6 +190,7 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
     }: Partial<ISSUE.IssueSubmitValues> = initialValues ?? {};
     const resolvedEventData = initial.eventData;
     const resolvedRoles = initial.teamVisibilityIds ?? defaults.roles;
+    const resolvedAssigneeIds = initial.assigneeIds ?? defaults.assigneeIds;
     if (initial.isEvent) {
       return {
         ...defaults,
@@ -200,6 +201,7 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
         links: initial.links ?? defaults.links,
         date: normalizeTaskDueDate(initial.date ?? defaults.date),
         roles: resolvedRoles,
+        assigneeIds: resolvedAssigneeIds,
       };
     }
     return {
@@ -211,6 +213,7 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
       date: normalizeTaskDueDate(initial.date ?? defaults.date),
       links: initial.links ?? defaults.links,
       roles: resolvedRoles,
+      assigneeIds: resolvedAssigneeIds,
     };
   }, [initialValues]);
   const [formValues, setFormValues] = useState<ISSUE.IssueEditNode>(
@@ -262,6 +265,16 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
 
   const baseId = useId();
   const effectiveTeam = formValues.team || (rolesData?.[0]?.id ?? "");
+  const usersOnTeamQuery = api.issues.getUsersOnTeam.useQuery(
+    { teamId: effectiveTeam },
+    { enabled: isOpen && !!effectiveTeam },
+  );
+  const assigneesForTeam = useMemo<ISSUE.IssueAssigneeOption[]>(
+    () => usersOnTeamQuery.data ?? [],
+    [usersOnTeamQuery.data],
+  );
+  const isAssigneesLoading = usersOnTeamQuery.isLoading;
+  const assigneesError = usersOnTeamQuery.error;
 
   const isFormValid = issueFormSchema.safeParse({
     ...formValues,
@@ -285,6 +298,17 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
       ),
     [formValues.eventData?.roles, roleIdSet],
   );
+  const assigneeIdSet = useMemo(
+    () => new Set(assigneesForTeam.map((user) => user.id)),
+    [assigneesForTeam],
+  );
+  const safeAssigneeIds = useMemo(
+    () =>
+      usersOnTeamQuery.isSuccess
+        ? formValues.assigneeIds.filter((userId) => assigneeIdSet.has(userId))
+        : formValues.assigneeIds,
+    [assigneeIdSet, formValues.assigneeIds, usersOnTeamQuery.isSuccess],
+  );
 
   // Helper for event form
   const updateEventData = <K extends keyof ISSUE.EventFormValues>(
@@ -410,7 +434,7 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
       team: effectiveTeam,
       teamVisibilityIds:
         safeVisibilityIds.length > 0 ? safeVisibilityIds : undefined,
-      assigneeIds: formValues.assigneeIds,
+      assigneeIds: safeAssigneeIds,
     };
 
     try {
@@ -481,7 +505,7 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
             : normalizeTaskDueDate(formValues.date),
           teamVisibilityIds:
             safeVisibilityIds.length > 0 ? safeVisibilityIds : undefined,
-          assigneeIds: formValues.assigneeIds,
+          assigneeIds: safeAssigneeIds,
         });
 
         await utils.issues.invalidate();
@@ -522,7 +546,7 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
         eventData: formValues.eventData,
         teamVisibilityIds:
           safeVisibilityIds.length > 0 ? safeVisibilityIds : undefined,
-        assigneeIds: formValues.assigneeIds,
+        assigneeIds: safeAssigneeIds,
       });
     }
   };
@@ -663,13 +687,91 @@ export function CreateEditDialog(props: CreateEditDialogComponentProps) {
                   <TeamSelect
                     className={cn(baseField, "col-span-3")}
                     value={effectiveTeam}
-                    onValueChange={(v) => updateForm("team", v)}
+                    onValueChange={(v) => {
+                      setFormValues((previous) => ({
+                        ...previous,
+                        team: v,
+                        assigneeIds: [],
+                      }));
+                    }}
                     roles={rolesData ?? []}
                     isLoading={isRolesLoading}
                     error={rolesError}
                   />
                 </div>
 
+                <div className="grid grid-cols-4 items-start gap-4">
+                  <Label className="mt-1 text-right text-sm">Assignees</Label>
+                  <div className="col-span-3 mt-1 grid grid-cols-2 gap-x-2 gap-y-3">
+                    {isAssigneesLoading && (
+                      <p className="col-span-2 text-sm text-muted-foreground">
+                        Loading team members...
+                      </p>
+                    )}
+
+                    {!!assigneesError && (
+                      <p className="col-span-2 text-sm text-destructive">
+                        Failed to load team members
+                      </p>
+                    )}
+
+                    {!isAssigneesLoading &&
+                      !assigneesError &&
+                      assigneesForTeam.length === 0 && (
+                        <p className="col-span-2 text-sm text-muted-foreground">
+                          No team members found for this team
+                        </p>
+                      )}
+
+                    {!isAssigneesLoading &&
+                      !assigneesError &&
+                      assigneesForTeam.map((user) => {
+                        const assigneeCheckboxId = `${baseId}-assignee-${user.id}`;
+                        return (
+                          <div
+                            key={user.id}
+                            className="flex flex-row items-start space-x-3 space-y-0"
+                          >
+                            <Checkbox
+                              id={assigneeCheckboxId}
+                              checked={formValues.assigneeIds.includes(user.id)}
+                              onCheckedChange={(checked) => {
+                                const selectedIds = formValues.assigneeIds;
+                                updateForm(
+                                  "assigneeIds",
+                                  checked
+                                    ? Array.from(
+                                        new Set([...selectedIds, user.id]),
+                                      )
+                                    : selectedIds.filter(
+                                        (id) => id !== user.id,
+                                      ),
+                                );
+                              }}
+                            />
+                            <div className="flex flex-col">
+                              <Label
+                                htmlFor={assigneeCheckboxId}
+                                className="cursor-pointer font-normal"
+                              >
+                                {user.name}
+                              </Label>
+                              {user.email && (
+                                <span className="text-xs text-muted-foreground">
+                                  {user.email}
+                                </span>
+                              )}
+                            </div>
+                          </div>
+                        );
+                      })}
+
+                    <p className="col-span-2 text-sm font-normal text-gray-400">
+                      Select one or more team members responsible for this issue
+                    </p>
+                  </div>
+                </div>
+
                 <div className="grid grid-cols-4 items-start gap-4">
                   <Label
                     htmlFor={`${baseId}-internal-description`}
diff --git a/packages/api/src/routers/issues.ts b/packages/api/src/routers/issues.ts
index 5d04f94db..76f85f7ab 100644
--- a/packages/api/src/routers/issues.ts
+++ b/packages/api/src/routers/issues.ts
@@ -5,7 +5,7 @@ import { z } from "zod";
 import { ISSUE } from "@forge/consts";
 import { and, eq, exists, inArray, sql } from "@forge/db";
 import { db } from "@forge/db/client";
-import { Permissions } from "@forge/db/schemas/auth";
+import { Permissions, User } from "@forge/db/schemas/auth";
 import {
   InsertTemplateSchema,
   Issue,
@@ -15,6 +15,7 @@ import {
   Template,
 } from "@forge/db/schemas/knight-hacks";
 import { permissions } from "@forge/utils";
+import * as permissionsServer from "@forge/utils/permissions.server";
 
 import { permProcedure } from "../trpc";
 
@@ -112,6 +113,48 @@ const issueTemplateSchema: z.ZodType<IssueTemplate> =
   });
 
 export const issuesRouter = {
+  getUsersOnTeam: permProcedure
+    .input(
+      z.object({
+        teamId: z.string().uuid(),
+      }),
+    )
+    .query(async ({ ctx, input }) => {
+      permissions.controlPerms.or(["EDIT_ISSUES"], ctx);
+
+      const rows = await db
+        .select({
+          id: User.id,
+          name: User.name,
+          email: User.email,
+          discordUserId: User.discordUserId,
+        })
+        .from(User)
+        .innerJoin(Permissions, eq(User.id, Permissions.userId))
+        .where(eq(Permissions.roleId, input.teamId));
+
+      const userById = new Map<
+        string,
+        {
+          id: string;
+          name: string;
+          email: string | null;
+        }
+      >();
+
+      for (const row of rows) {
+        userById.set(row.id, {
+          id: row.id,
+          name: row.name ?? row.email ?? row.discordUserId,
+          email: row.email,
+        });
+      }
+
+      return [...userById.values()].sort((a, b) =>
+        a.name.localeCompare(b.name),
+      );
+    }),
+
   createIssue: permProcedure
     .input(
       CreateIssueInputSchema.omit({ creator: true }).extend({
@@ -124,6 +167,15 @@ export const issuesRouter = {
       return await db.transaction(async (tx) => {
         const { teamVisibilityIds, assigneeIds, children, ...rest } = input;
 
+        await permissionsServer.validateAssigneesBelongToTeam(
+          tx,
+          input.team,
+          assigneeIds,
+        );
+        if (children?.length) {
+          await permissionsServer.validateIssueNodeAssignees(tx, children);
+        }
+
         const [issue] = await tx
           .insert(Issue)
           .values({
@@ -316,59 +368,89 @@ export const issuesRouter = {
     )
     .mutation(async ({ ctx, input }) => {
       permissions.controlPerms.or(["EDIT_ISSUES"], ctx);
-      await requireIssue(input.id);
+      return await db.transaction(async (tx) => {
+        const existingIssue = await tx.query.Issue.findFirst({
+          where: (t, { eq }) => eq(t.id, input.id),
+          with: {
+            userAssignments: true,
+          },
+        });
 
-      const { id, assigneeIds, teamVisibilityIds, ...fields } = input;
-      const updateData = Object.fromEntries(
-        (Object.entries(fields) as [string, unknown][]).filter(
-          ([, v]) => v !== undefined,
-        ),
-      );
+        if (!existingIssue) {
+          throw new TRPCError({
+            message: "Issue not found.",
+            code: "NOT_FOUND",
+          });
+        }
 
-      if (Object.keys(updateData).length > 0) {
-        await db.update(Issue).set(updateData).where(eq(Issue.id, id));
-      }
+        const assignmentTeamId = input.team ?? existingIssue.team;
+        const existingAssigneeIds = existingIssue.userAssignments.map(
+          (assignment) => assignment.userId,
+        );
+        const assigneeIdsToValidate =
+          input.assigneeIds ??
+          (input.team !== undefined && input.team !== existingIssue.team
+            ? existingAssigneeIds
+            : undefined);
+
+        await permissionsServer.validateAssigneesBelongToTeam(
+          tx,
+          assignmentTeamId,
+          assigneeIdsToValidate,
+        );
 
-      if (teamVisibilityIds !== undefined) {
-        await db
-          .delete(IssuesToTeamsVisibility)
-          .where(eq(IssuesToTeamsVisibility.issueId, id));
-        if (teamVisibilityIds.length > 0) {
-          await db
-            .insert(IssuesToTeamsVisibility)
-            .values(
-              teamVisibilityIds.map((teamId) => ({ issueId: id, teamId })),
-            );
+        const { id, assigneeIds, teamVisibilityIds, ...fields } = input;
+        const updateData = Object.fromEntries(
+          (Object.entries(fields) as [string, unknown][]).filter(
+            ([, v]) => v !== undefined,
+          ),
+        );
+
+        if (Object.keys(updateData).length > 0) {
+          await tx.update(Issue).set(updateData).where(eq(Issue.id, id));
         }
-      }
 
-      if (assigneeIds !== undefined) {
-        await db
-          .delete(IssuesToUsersAssignment)
-          .where(eq(IssuesToUsersAssignment.issueId, id));
-        if (assigneeIds.length > 0) {
-          await db
-            .insert(IssuesToUsersAssignment)
-            .values(assigneeIds.map((userId) => ({ issueId: id, userId })));
+        if (teamVisibilityIds !== undefined) {
+          await tx
+            .delete(IssuesToTeamsVisibility)
+            .where(eq(IssuesToTeamsVisibility.issueId, id));
+          if (teamVisibilityIds.length > 0) {
+            await tx
+              .insert(IssuesToTeamsVisibility)
+              .values(
+                teamVisibilityIds.map((teamId) => ({ issueId: id, teamId })),
+              );
+          }
         }
-      }
 
-      if (
-        Object.keys(updateData).length === 0 &&
-        (teamVisibilityIds !== undefined || assigneeIds !== undefined)
-      ) {
-        await db
-          .update(Issue)
-          .set({ updatedAt: new Date() })
-          .where(eq(Issue.id, id));
-      }
+        if (assigneeIds !== undefined) {
+          await tx
+            .delete(IssuesToUsersAssignment)
+            .where(eq(IssuesToUsersAssignment.issueId, id));
+          if (assigneeIds.length > 0) {
+            await tx
+              .insert(IssuesToUsersAssignment)
+              .values(assigneeIds.map((userId) => ({ issueId: id, userId })));
+          }
+        }
 
-      return db.query.Issue.findFirst({
-        where: (t, { eq }) => eq(t.id, id),
-        with: {
-          teamVisibility: { with: { team: true } },
-          userAssignments: { with: { user: true } },
-        },
+        if (
+          Object.keys(updateData).length === 0 &&
+          (teamVisibilityIds !== undefined || assigneeIds !== undefined)
+        ) {
+          await tx
+            .update(Issue)
+            .set({ updatedAt: new Date() })
+            .where(eq(Issue.id, id));
+        }
+
+        return tx.query.Issue.findFirst({
+          where: (t, { eq }) => eq(t.id, id),
+          with: {
+            teamVisibility: { with: { team: true } },
+            userAssignments: { with: { user: true } },
+          },
+        });
       });
     }),
   deleteIssue: permProcedure
diff --git a/packages/consts/src/issue.ts b/packages/consts/src/issue.ts
index fb60d50d0..9241a24b1 100644
--- a/packages/consts/src/issue.ts
+++ b/packages/consts/src/issue.ts
@@ -88,6 +88,12 @@ export interface CreateEditDialogProps {
   onDelete?: (values: IssueSubmitValues) => void;
 }
 
+export interface IssueAssigneeOption {
+  id: UUID;
+  name: string;
+  email?: string | null;
+}
+
 type IssueStatus = (typeof ISSUE_STATUS)[number];
 type IssuePriority = (typeof PRIORITY)[number];
 export type UUID = string;
@@ -107,7 +113,7 @@ export interface IssueEditNode {
   event?: UUID | null;
   eventData?: EventFormValues;
   roles: string[];
-  assigneeIds?: string[];
+  assigneeIds: UUID[];
   children: IssueEditNode[];
 }
 
diff --git a/packages/utils/src/permissions.server.ts b/packages/utils/src/permissions.server.ts
index b401da71b..de4e03b52 100644
--- a/packages/utils/src/permissions.server.ts
+++ b/packages/utils/src/permissions.server.ts
@@ -1,10 +1,11 @@
 import "server-only";
 
 import { cookies } from "next/headers";
-import { and, eq, gt } from "drizzle-orm";
+import { TRPCError } from "@trpc/server";
+import { and, eq, gt, inArray } from "drizzle-orm";
 
 import { db } from "@forge/db/client";
-import { JudgeSession } from "@forge/db/schemas/auth";
+import { JudgeSession, Permissions } from "@forge/db/schemas/auth";
 
 import { logger } from "./logger";
 
@@ -59,3 +60,61 @@ export const getJudgeSessionFromCookie = async () => {
 
   return rows[0] ?? null;
 };
+
+interface IssueAssigneeValidationNode {
+  team: string;
+  assigneeIds?: string[];
+  children?: IssueAssigneeValidationNode[];
+}
+
+type DbExecutor =
+  | typeof db
+  | Parameters<Parameters<typeof db.transaction>[0]>[0];
+
+export const validateAssigneesBelongToTeam = async (
+  executor: DbExecutor,
+  teamId: string,
+  assigneeIds: string[] | undefined,
+) => {
+  if (!assigneeIds || assigneeIds.length === 0) {
+    return;
+  }
+
+  const uniqueAssigneeIds = [...new Set(assigneeIds)];
+
+  const rows = await executor
+    .select({ userId: Permissions.userId })
+    .from(Permissions)
+    .where(
+      and(
+        eq(Permissions.roleId, teamId),
+        inArray(Permissions.userId, uniqueAssigneeIds),
+      ),
+    );
+
+  const validAssigneeIdSet = new Set(rows.map((row) => row.userId));
+  const invalidAssigneeIds = uniqueAssigneeIds.filter(
+    (assigneeId) => !validAssigneeIdSet.has(assigneeId),
+  );
+
+  if (invalidAssigneeIds.length > 0) {
+    throw new TRPCError({
+      code: "BAD_REQUEST",
+      message:
+        "All assignees must belong to the selected team. Invalid assignee IDs: " +
+        invalidAssigneeIds.join(", "),
+    });
+  }
+};
+
+export const validateIssueNodeAssignees = async (
+  executor: DbExecutor,
+  nodes: IssueAssigneeValidationNode[],
+) => {
+  for (const node of nodes) {
+    await validateAssigneesBelongToTeam(executor, node.team, node.assigneeIds);
+    if (node.children?.length) {
+      await validateIssueNodeAssignees(executor, node.children);
+    }
+  }
+};