diff --git a/client/src/components/appointmentCard/AppointmentCard.tsx b/client/src/components/appointmentCard/AppointmentCard.tsx
index 7a941eed..4f5d28e4 100644
--- a/client/src/components/appointmentCard/AppointmentCard.tsx
+++ b/client/src/components/appointmentCard/AppointmentCard.tsx
@@ -3,6 +3,7 @@ import { AppointmentStatusBar } from "./AppointmentStatusBar";
 import { AppointmentAvatar } from "./AppointmentAvatar";
 import { AppointmentInfo } from "./AppointmentInfo";
 import { AppointmentJoinButton } from "./AppointmentJoinButton";
+import { RejectionReasonDisplay } from "./RejectionReasonDisplay";
 import {
   getStatusStyles,
   isInternalVideoCallLink,
@@ -69,6 +70,8 @@ export const AppointmentCard = ({
           onDelete={isPast ? onDelete : undefined}
         />
       </div>
+
+      <RejectionReasonDisplay appointment={appointment} />
     </div>
   );
 };
diff --git a/client/src/components/appointmentCard/RejectAppointmentModal.tsx b/client/src/components/appointmentCard/RejectAppointmentModal.tsx
new file mode 100644
index 00000000..cbdc21f8
--- /dev/null
+++ b/client/src/components/appointmentCard/RejectAppointmentModal.tsx
@@ -0,0 +1,132 @@
+import React, { useState } from "react";
+import { Appointment } from "../../types/appointments.types";
+import { useUpdateAppointmentMutation } from "../../features/appointments/mutations/useUpdateAppointmentMutation";
+
+interface RejectAppointmentModalProps {
+  appointment: Appointment;
+  isOpen: boolean;
+  onClose: () => void;
+}
+
+export const RejectAppointmentModal = ({
+  appointment,
+  isOpen,
+  onClose,
+}: RejectAppointmentModalProps) => {
+  const [rejectionReason, setRejectionReason] = useState("");
+  const [error, setError] = useState("");
+  const updateAppointmentMutation = useUpdateAppointmentMutation();
+
+  const handleSubmit = async (e: React.FormEvent) => {
+    e.preventDefault();
+
+    if (rejectionReason.trim().length < 100) {
+      setError("Rejection reason must be at least 100 characters");
+      return;
+    }
+
+    if (rejectionReason.trim().length > 500) {
+      setError("Rejection reason must not exceed 500 characters");
+      return;
+    }
+
+    try {
+      await updateAppointmentMutation.mutateAsync({
+        appointmentId: appointment.id,
+        status: "rejected",
+        rejectionReason: rejectionReason.trim(),
+      });
+      onClose();
+      setRejectionReason("");
+      setError("");
+    } catch {
+      setError("Failed to reject appointment. Please try again.");
+    }
+  };
+
+  const handleClose = () => {
+    onClose();
+    setRejectionReason("");
+    setError("");
+  };
+
+  if (!isOpen) return null;
+
+  return (
+    <div className="fixed inset-0 backdrop-blur-sm bg-white/5 flex items-center justify-center z-50">
+      <div className="bg-white rounded-lg p-6 w-full max-w-md mx-4">
+        <h2 className="text-xl font-semibold mb-4">Reject Appointment</h2>
+
+        <div className="mb-4">
+          <p className="text-sm text-gray-600 mb-2">
+            <strong>Student:</strong> {appointment.studentName}
+          </p>
+          <p className="text-sm text-gray-600 mb-2">
+            <strong>Lesson:</strong> {appointment.lesson}
+          </p>
+          <p className="text-sm text-gray-600 mb-4">
+            <strong>Date & Time:</strong> {appointment.date} at{" "}
+            {appointment.time}
+          </p>
+        </div>
+
+        <form onSubmit={handleSubmit}>
+          <div className="mb-4">
+            <label
+              htmlFor="rejectionReason"
+              className="block text-sm font-medium text-gray-700 mb-2"
+            >
+              Reason for Rejection *
+            </label>
+            <textarea
+              id="rejectionReason"
+              value={rejectionReason}
+              onChange={(e) => setRejectionReason(e.target.value)}
+              className="w-full p-3 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-transparent resize-none"
+              rows={6}
+              placeholder="Please explain why you are rejecting this appointment (100-500 characters)..."
+              required
+            />
+            <div className="flex justify-between text-xs text-gray-500 mt-1">
+              <span>Minimum 100 characters</span>
+              <span
+                className={rejectionReason.length > 500 ? "text-red-500" : ""}
+              >
+                {rejectionReason.length}/500
+              </span>
+            </div>
+          </div>
+
+          {error && (
+            <div className="mb-4 p-3 bg-red-50 border border-red-200 rounded-lg">
+              <p className="text-sm text-red-700">{error}</p>
+            </div>
+          )}
+
+          <div className="flex gap-3">
+            <button
+              type="button"
+              onClick={handleClose}
+              className="flex-1 px-4 py-2 text-gray-700 bg-gray-100 rounded-lg hover:bg-gray-200 transition-colors"
+              disabled={updateAppointmentMutation.isPending}
+            >
+              Cancel
+            </button>
+            <button
+              type="submit"
+              className="flex-1 px-4 py-2 text-white bg-red-600 rounded-lg hover:bg-red-700 transition-colors disabled:opacity-50"
+              disabled={
+                updateAppointmentMutation.isPending ||
+                rejectionReason.trim().length < 100
+              }
+            >
+              {updateAppointmentMutation.isPending
+                ? "Rejecting..."
+                : "Reject Appointment"}
+            </button>
+          </div>
+        </form>
+      </div>
+    </div>
+  );
+};
diff --git a/client/src/components/appointmentCard/RejectionReasonDisplay.tsx b/client/src/components/appointmentCard/RejectionReasonDisplay.tsx
new file mode 100644
index 00000000..5683f7d6
--- /dev/null
+++ b/client/src/components/appointmentCard/RejectionReasonDisplay.tsx
@@ -0,0 +1,24 @@
+import { Appointment } from "../../types/appointments.types";
+
+interface RejectionReasonDisplayProps {
+  appointment: Appointment;
+}
+
+export const RejectionReasonDisplay = ({
+  appointment,
+}: RejectionReasonDisplayProps) => {
+  if (appointment.status !== "rejected" || !appointment.rejectionReason) {
+    return null;
+  }
+
+  return (
+    <div className="mt-3 p-3 bg-red-50 border border-red-200 rounded-lg">
+      <h4 className="text-sm font-medium text-red-800 mb-2">
+        Reason for Rejection:
+      </h4>
+      <p className="text-sm text-red-700 leading-relaxed">
+        {appointment.rejectionReason}
+      </p>
+    </div>
+  );
+};
diff --git a/client/src/components/ui/statusButtons/StatusButtons.tsx b/client/src/components/ui/statusButtons/StatusButtons.tsx
index 1ad6d28d..5541cf2e 100644
--- a/client/src/components/ui/statusButtons/StatusButtons.tsx
+++ b/client/src/components/ui/statusButtons/StatusButtons.tsx
@@ -26,7 +26,11 @@ export const StatusButtons = ({
     if (disabled) return;
     event.preventDefault();
     event.stopPropagation();
-    setStatus(newStatus);
+
+    if (newStatus !== "rejected") {
+      setStatus(newStatus);
+    }
+
     onStatusChange?.(newStatus);
   };
 
diff --git a/client/src/features/appointments/mutations/useUpdateAppointmentMutation.ts b/client/src/features/appointments/mutations/useUpdateAppointmentMutation.ts
index 084a23e5..b32a7046 100644
--- a/client/src/features/appointments/mutations/useUpdateAppointmentMutation.ts
+++ b/client/src/features/appointments/mutations/useUpdateAppointmentMutation.ts
@@ -11,14 +11,23 @@ import { getErrorMessage } from "../../../util/ErrorUtil";
 interface UpdateAppointmentRequest {
   appointmentId: string;
   status: AppointmentStatus;
+  rejectionReason?: string;
 }
 
 const updateAppointmentStatus = async (
   data: UpdateAppointmentRequest,
 ): Promise<Appointment> => {
+  const requestBody: { status: AppointmentStatus; rejectionReason?: string } = {
+    status: data.status,
+  };
+
+  if (data.rejectionReason) {
+    requestBody.rejectionReason = data.rejectionReason;
+  }
+
   const response = await apiProtected.put<Appointment>(
     `/api/appointments/${data.appointmentId}/status`,
-    { status: data.status },
+    requestBody,
   );
   return response.data;
 };
diff --git a/client/src/pages/privetTeachersPages/teacherAppointments/TeacherAppointments.tsx b/client/src/pages/privetTeachersPages/teacherAppointments/TeacherAppointments.tsx
index 56bbfa37..c5c13043 100644
--- a/client/src/pages/privetTeachersPages/teacherAppointments/TeacherAppointments.tsx
+++ b/client/src/pages/privetTeachersPages/teacherAppointments/TeacherAppointments.tsx
@@ -14,6 +14,7 @@ import { useVideoCall } from "../../../features/appointments/hooks/useVideoCall"
 import { useAppointmentTime } from "../../../features/appointments/hooks/useAppointmentTime";
 import { TeacherAppointmentsList } from "../../../components/teacherAppointmentCard/TeacherAppointmentsList";
 import { RegularStudentScheduleModal } from "../../../components/regularStudentScheduleModal/RegularStudentScheduleModal";
+import { RejectAppointmentModal } from "../../../components/appointmentCard/RejectAppointmentModal";
 import { useSetRegularStudentMutation } from "../../../features/appointments/mutations/useSetRegularStudentMutation";
 import { useUpdateWeeklyScheduleMutation } from "../../../features/appointments/mutations/useUpdateWeeklyScheduleMutation";
 import { useRemoveRegularStudentMutation } from "../../../features/appointments/mutations/useRemoveRegularStudentMutation";
@@ -30,6 +31,9 @@ export const TeacherAppointments = () => {
   const [selectedStudent, setSelectedStudent] = useState<Appointment | null>(
     null,
   );
+  const [isRejectModalOpen, setIsRejectModalOpen] = useState(false);
+  const [appointmentToReject, setAppointmentToReject] =
+    useState<Appointment | null>(null);
 
   const { open: openModal } = useModalStore();
   const { confirmStartCall } = useVideoCall();
@@ -74,6 +78,15 @@ export const TeacherAppointments = () => {
     appointmentId: string,
     newStatus: AppointmentStatus,
   ) => {
+    if (newStatus === "rejected") {
+      const appointment = appointments.find((apt) => apt.id === appointmentId);
+      if (appointment) {
+        setAppointmentToReject(appointment);
+        setIsRejectModalOpen(true);
+      }
+      return;
+    }
+
     updateAppointmentMutation.mutate({
       appointmentId,
       status: newStatus,
@@ -241,6 +254,17 @@ export const TeacherAppointments = () => {
             .flatMap((apt) => apt.weeklySchedule || []) || []
         }
       />
+
+      {appointmentToReject && (
+        <RejectAppointmentModal
+          appointment={appointmentToReject}
+          isOpen={isRejectModalOpen}
+          onClose={() => {
+            setIsRejectModalOpen(false);
+            setAppointmentToReject(null);
+          }}
+        />
+      )}
     </div>
   );
 };
diff --git a/client/src/types/appointments.types.ts b/client/src/types/appointments.types.ts
index dd28f4e6..79789a18 100644
--- a/client/src/types/appointments.types.ts
+++ b/client/src/types/appointments.types.ts
@@ -14,6 +14,7 @@ export interface Appointment {
   time: string;
   description?: string;
   status: AppointmentStatus;
+  rejectionReason?: string;
   videoCall?: string;
   isRegularStudent?: boolean;
   addedToRegularAt?: string;
diff --git a/server/src/db/schemes/appointmentSchema.ts b/server/src/db/schemes/appointmentSchema.ts
index 6b2e6eaa..a4605424 100644
--- a/server/src/db/schemes/appointmentSchema.ts
+++ b/server/src/db/schemes/appointmentSchema.ts
@@ -29,6 +29,7 @@ export const AppointmentSchema = new mongoose.Schema<AppointmentTypeDB>(
       enum: ["pending", "approved", "rejected"],
       default: "pending",
     },
+    rejectionReason: { type: String, default: null },
     videoCall: { type: String, default: null },
     isRegularStudent: { type: Boolean, default: false },
     weeklySchedule: [weeklyScheduleSlotSchema],
diff --git a/server/src/db/schemes/types/appointment.types.ts b/server/src/db/schemes/types/appointment.types.ts
index 28076b2f..914e8397 100644
--- a/server/src/db/schemes/types/appointment.types.ts
+++ b/server/src/db/schemes/types/appointment.types.ts
@@ -19,6 +19,7 @@ export interface AppointmentTypeDB {
   time: string;
   description?: string;
   status: "pending" | "approved" | "rejected";
+  rejectionReason?: string;
   videoCall?: string;
   isRegularStudent?: boolean;
   weeklySchedule?: WeeklyScheduleSlot[];
diff --git a/server/src/services/appointment/appointment.service.ts b/server/src/services/appointment/appointment.service.ts
index b4df5bfb..89f3cfd8 100644
--- a/server/src/services/appointment/appointment.service.ts
+++ b/server/src/services/appointment/appointment.service.ts
@@ -111,6 +111,22 @@ export class AppointmentService {
   }
 
   async updateAppointmentStatus(id: string, data: UpdateAppointmentStatusType) {
+    if (data.status === "rejected") {
+      if (!data.rejectionReason) {
+        throw new Error(
+          "Rejection reason is required when rejecting an appointment",
+        );
+      }
+      if (
+        data.rejectionReason.length < 100 ||
+        data.rejectionReason.length > 500
+      ) {
+        throw new Error(
+          "Rejection reason must be between 100 and 500 characters",
+        );
+      }
+    }
+
     const updateData = {
       ...data,
       updatedAt: new Date(),
@@ -258,6 +274,7 @@ export class AppointmentService {
       time: string;
       description?: string;
       status: string;
+      rejectionReason?: string;
       videoCall?: string;
       isRegularStudent?: boolean;
       weeklySchedule?: { day: string; hour: number }[];
@@ -281,6 +298,7 @@ export class AppointmentService {
       time: apt.time,
       description: apt.description,
       status: apt.status,
+      rejectionReason: apt.rejectionReason,
       videoCall: apt.videoCall,
       isRegularStudent: apt.isRegularStudent,
       weeklySchedule: apt.weeklySchedule,
diff --git a/server/src/types/appointment/appointment.types.ts b/server/src/types/appointment/appointment.types.ts
index d4ae26d6..2b4d1f8d 100644
--- a/server/src/types/appointment/appointment.types.ts
+++ b/server/src/types/appointment/appointment.types.ts
@@ -15,6 +15,7 @@ export interface CreateAppointmentType {
 
 export interface UpdateAppointmentStatusType {
   status: "pending" | "approved" | "rejected";
+  rejectionReason?: string;
 }
 
 export interface UpdateWeeklyScheduleType {
diff --git a/server/src/validation/appointment/appointmentValidationMiddleware.ts b/server/src/validation/appointment/appointmentValidationMiddleware.ts
index 35b1592a..5bb35d68 100644
--- a/server/src/validation/appointment/appointmentValidationMiddleware.ts
+++ b/server/src/validation/appointment/appointmentValidationMiddleware.ts
@@ -29,6 +29,13 @@ export const updateAppointmentStatusValidationMiddleware = () => [
     .withMessage("Status is needed")
     .isIn(["pending", "approved", "rejected"])
     .withMessage("Status must be pending, approved, or rejected"),
+  body("rejectionReason")
+    .if(body("status").equals("rejected"))
+    .notEmpty()
+    .withMessage("Rejection reason is required when rejecting an appointment")
+    .isLength({ min: 100, max: 500 })
+    .withMessage("Rejection reason must be between 100 and 500 characters")
+    .trim(),
 ];
 
 export const idParamValidationMiddleware = () => [
diff --git a/server/src/validation/appointment/rejectionReasonValidation.ts b/server/src/validation/appointment/rejectionReasonValidation.ts
new file mode 100644
index 00000000..ea8b065c
--- /dev/null
+++ b/server/src/validation/appointment/rejectionReasonValidation.ts
@@ -0,0 +1,16 @@
+import { check } from "express-validator";
+
+export const rejectionReasonValidation = check("rejectionReason")
+  .if(check("status").equals("rejected"))
+  .notEmpty()
+  .withMessage("Rejection reason is required when rejecting an appointment")
+  .isLength({ min: 100, max: 500 })
+  .withMessage("Rejection reason must be between 100 and 500 characters")
+  .trim();
+
+export const appointmentStatusUpdateValidation = [
+  check("status")
+    .isIn(["pending", "approved", "rejected"])
+    .withMessage("Status must be pending, approved, or rejected"),
+  rejectionReasonValidation,
+];