diff --git a/css/common.css b/css/common.css
index 24e665f0..74eb7e99 100644
--- a/css/common.css
+++ b/css/common.css
@@ -24,6 +24,7 @@
   --color-input: #f3f4f6;
   --color-white: #ffffff;
   --color-text-login: #1f2937;
+  --color-error-red: #f74747;
 
   /* Typography */
   --font-primary: "Pretendard-Regular", sans-serif;
@@ -58,3 +59,7 @@ body {
   background-color: var(--color-disabled);
 }
 /* 비활성화시에 속성이랑 클래스 둘다 넣어야 함 */
+
+.display-none {
+  display: none;
+}
diff --git a/css/login-signup-style.css b/css/login-signup-style.css
index b73ef144..c84e4894 100644
--- a/css/login-signup-style.css
+++ b/css/login-signup-style.css
@@ -46,17 +46,31 @@ main {
   font-size: 16px;
 }
 
+.form__input.invalid {
+  border: 1px solid var(--color-error-red);
+}
+
+.form__error-msg {
+  position: relative;
+  top: -12px;
+  padding-left: 16px;
+  color: var(--color-error-red);
+  font-weight: 500;
+  font-size: 14px;
+}
+
 .input--password {
   position: relative;
 }
 
-.btn--visibility-off {
+.btn--visibility {
   border: none;
   background-color: var(--color-input);
   position: absolute;
   top: 16px;
   right: 24px;
   bottom: 16px;
+  padding: 0;
 }
 
 .btn--interactions {
diff --git a/faq.html b/faq.html
index e69de29b..93e4fdf5 100644
--- a/faq.html
+++ b/faq.html
@@ -0,0 +1 @@
+<!--  -->
diff --git a/index.html b/index.html
index b3ead464..5d17cbb3 100644
--- a/index.html
+++ b/index.html
@@ -9,7 +9,7 @@
     />
     <meta property="og:title" content="판다 마켓" />
     <meta property="og:type" content="website" />
-    <meta property="og:image" content="img/panda-market_thumbnail.png" />
+    <meta property="og:image" content="assets/img/panda-market_thumbnail.png" />
     <meta property="og:description" content="일상의 모든 물건을 거래해보세요" />
     <title>판다마켓</title>
     <link rel="stylesheet" href="css/index-style.css" />
diff --git a/js/btn-functions.js b/js/btn-functions.js
new file mode 100644
index 00000000..4a031a67
--- /dev/null
+++ b/js/btn-functions.js
@@ -0,0 +1,24 @@
+//모든 input의 유효성 검사를 통과했을 때에만 누를 수 있어야하므로 validate와 작동방식이 달라야함
+export function toggleBtnStatus() {
+  const btn = document.querySelector(".btn--interactions");
+  const errorMessages = document.querySelectorAll(".form__error-msg");
+  const inputs = document.querySelectorAll(".form__input");
+
+  for (const message of errorMessages) {
+    if (message.textContent) {
+      btn.setAttribute("disabled", "");
+      btn.classList.add("btn--disabled");
+      return;
+    }
+  }
+  for (const input of inputs) {
+    if (!input.value) {
+      btn.setAttribute("disabled", "");
+      btn.classList.add("btn--disabled");
+      return;
+    }
+  }
+
+  btn.removeAttribute("disabled");
+  btn.classList.remove("btn--disabled");
+}
diff --git a/js/login-signup.js b/js/login-signup.js
new file mode 100644
index 00000000..42fc036c
--- /dev/null
+++ b/js/login-signup.js
@@ -0,0 +1,60 @@
+import {
+  isEmpty,
+  validateEmail,
+  validatePassword,
+  validatePasswordConfirm,
+  validatePasswordConfirmReverse,
+  validateNickname,
+} from "./validate.js";
+import { toggleBtnStatus } from "./btn-functions.js";
+
+function toggleVisibility(event) {
+  const btn = event.target.parentElement;
+  const passwordInput = btn.previousElementSibling;
+  const iconOff = btn.children[0];
+  const iconOn = btn.children[1];
+
+  if (passwordInput.getAttribute("type") === "password") {
+    passwordInput.setAttribute("type", "text");
+    btn.setAttribute("aria-pressed", "true");
+  } else {
+    passwordInput.setAttribute("type", "password");
+    btn.setAttribute("aria-pressed", "false");
+  }
+  iconOff.classList.toggle("display-none");
+  iconOn.classList.toggle("display-none");
+}
+
+function isSignupPage() {
+  return window.location.pathname.search("signup") === -1 ? false : true;
+}
+
+const form = document.querySelector(".container--form");
+const validateMap = {
+  email: validateEmail,
+  password: validatePassword,
+  "password-confirm": validatePasswordConfirm,
+  nickname: validateNickname,
+};
+
+form.addEventListener("focusout", (event) => {
+  const { id } = event.target;
+
+  if (validateMap[id]) {
+    validateMap[id](event);
+    //비밀번호확인란부터 입력후 비밀번호를 변경할 시 비밀번호 확인 유효성 검사
+    if (id === "password" && isSignupPage()) {
+      const passwordConfirmInput = document.getElementById("password-confirm");
+      const passwordConfirm = passwordConfirmInput.value;
+      if (!isEmpty(passwordConfirm)) {
+        validatePasswordConfirmReverse();
+      }
+    }
+    toggleBtnStatus();
+  }
+});
+form.addEventListener("click", (event) => {
+  if (event.target.classList.contains("form__icon")) {
+    toggleVisibility(event);
+  }
+});
diff --git a/js/validate.js b/js/validate.js
new file mode 100644
index 00000000..ce83eba6
--- /dev/null
+++ b/js/validate.js
@@ -0,0 +1,118 @@
+// common functions
+export function isEmpty(value) {
+  return value ? false : true;
+}
+
+function addInvalid(input) {
+  input.classList.add("invalid");
+}
+
+function removeInvalid(input) {
+  input.classList.remove("invalid");
+}
+
+// email functions
+const emailPattern = /^[A-Za-z0-9_\.\-]+@[A-Za-z0-9\-]+\.[A-Za-z0-9\-]+/;
+
+function checkEmailFormat(email) {
+  if (emailPattern.test(email)) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+export function validateEmail(event) {
+  const emailInput = event.target;
+  const email = emailInput.value;
+  let divErrorMessage = document.querySelector(".error-msg--email");
+
+  if (isEmpty(email)) {
+    divErrorMessage.textContent = "이메일을 입력해주세요";
+    addInvalid(emailInput);
+  } else if (!checkEmailFormat(email)) {
+    divErrorMessage.textContent = "잘못된 이메일 형식입니다";
+    addInvalid(emailInput);
+  } else {
+    divErrorMessage.textContent = "";
+    removeInvalid(emailInput);
+  }
+}
+
+// password functions
+function checkPasswordFormat(password) {
+  if (password.length < 8) {
+    return false;
+  } else {
+    return true;
+  }
+}
+
+function checkPassword(password, passwordConfirm) {
+  return password === passwordConfirm ? true : false;
+}
+
+export function validatePassword(event) {
+  const passwordInput = event.target;
+  const password = passwordInput.value;
+  let divErrorMessage = document.querySelector(".error-msg--password");
+
+  if (isEmpty(password)) {
+    divErrorMessage.textContent = "비밀번호를 입력해주세요";
+    addInvalid(passwordInput);
+  } else if (!checkPasswordFormat(password)) {
+    divErrorMessage.textContent = "비밀번호를 8자 이상 입력해주세요";
+    addInvalid(passwordInput);
+  } else {
+    divErrorMessage.textContent = "";
+    removeInvalid(passwordInput);
+  }
+}
+
+export function validatePasswordConfirm(event) {
+  const passwordInput = document.getElementById("password");
+  const password = passwordInput.value;
+  const passwordConfirmInput = event.target;
+  const passwordConfirm = passwordConfirmInput.value;
+  let divErrorMessage = document.querySelector(".error-msg--password-confirm");
+
+  if (!checkPassword(password, passwordConfirm)) {
+    divErrorMessage.textContent = "비밀번호가 일치하지 않습니다";
+    addInvalid(passwordConfirmInput);
+  } else {
+    divErrorMessage.textContent = "";
+    removeInvalid(passwordConfirmInput);
+  }
+}
+
+//password유효성 검사를 하면서 password-confirm검사를 하기 위해 event가 아닌 고정으로 값을 가져오도록 함
+export function validatePasswordConfirmReverse() {
+  const passwordInput = document.getElementById("password");
+  const password = passwordInput.value;
+  const passwordConfirmInput = document.getElementById("password-confirm");
+  const passwordConfirm = passwordConfirmInput.value;
+  let divErrorMessage = document.querySelector(".error-msg--password-confirm");
+
+  if (!checkPassword(password, passwordConfirm)) {
+    divErrorMessage.textContent = "비밀번호가 일치하지 않습니다";
+    addInvalid(passwordConfirmInput);
+  } else {
+    divErrorMessage.textContent = "";
+    removeInvalid(passwordConfirmInput);
+  }
+}
+
+//nickname functions
+export function validateNickname(event) {
+  const nicknameInput = event.target;
+  const nickname = nicknameInput.value;
+  let divErrorMessage = document.querySelector(".error-msg--nickname");
+
+  if (isEmpty(nickname)) {
+    divErrorMessage.textContent = "닉네임을 입력해주세요";
+    addInvalid(nicknameInput);
+  } else {
+    divErrorMessage.textContent = "";
+    removeInvalid(nicknameInput);
+  }
+}
diff --git a/login.html b/login.html
index 2557c53f..5ead6fd4 100644
--- a/login.html
+++ b/login.html
@@ -17,7 +17,12 @@
         <a href="/" class="btn btn--home">판다마켓</a>
       </div>
 
-      <form action="/" method="post" class="container container--form">
+      <form
+        action="/"
+        method="post"
+        novalidate
+        class="container container--form"
+      >
         <label for="email" class="form__label">이메일</label>
         <input
           id="email"
@@ -28,6 +33,7 @@
           placeholder="이메일을 입력해주세요"
           class="form__input"
         />
+        <div class="form__error-msg error-msg--email"></div>
 
         <label for="password" class="form__label">비밀번호</label>
         <div class="input--password">
@@ -36,25 +42,39 @@
             name="password"
             type="password"
             required
-            autocomplete="password"
+            autocomplete="off"
             placeholder="비밀번호를 입력해주세요"
             class="form__input"
           />
           <button
             type="button"
-            class="btn btn--visibility-off"
+            class="btn btn--visibility"
             aria-label="비밀번호 표시"
             aria-pressed="false"
           >
             <img
               src="assets/icons/btn_visibility_off.svg"
               alt="비밀번호를 보이지 않게끔 설정하는 눈에 빗금이 쳐진 아이콘입니다."
-              class="form__img"
+              class="form__icon"
+            />
+            <img
+              src="assets/icons/btn_visibility_on.svg"
+              alt="비밀번호를 보이게끔 설정하는 눈 모양의 아이콘입니다."
+              class="form__icon display-none"
             />
           </button>
         </div>
+        <div class="form__error-msg error-msg--password"></div>
 
-        <button type="submit" class="btn btn--interactions">로그인</button>
+        <!-- onclick 부분은 form제출 기능이 있다면 추후 변경 -->
+        <button
+          type="submit"
+          onclick="location.href='items.html'; return false;"
+          disabled
+          class="btn btn--interactions btn--disabled"
+        >
+          로그인
+        </button>
       </form>
 
       <div class="container container--easy-login">
@@ -84,5 +104,6 @@
         <a class="text--url" href="signup.html">회원가입</a>
       </div>
     </main>
+    <script type="module" defer src="js/login-signup.js"></script>
   </body>
 </html>
diff --git a/signup.html b/signup.html
index d9b1362c..edbf37bc 100644
--- a/signup.html
+++ b/signup.html
@@ -16,7 +16,12 @@
         />
         <a href="/" class="btn btn--home">판다마켓</a>
       </div>
-      <form action="/" method="post" class="container container--form">
+      <form
+        action="/"
+        method="post"
+        novalidate
+        class="container container--form"
+      >
         <label for="email" class="form__label">이메일</label>
         <input
           id="email"
@@ -27,6 +32,7 @@
           placeholder="이메일을 입력해주세요"
           class="form__input"
         />
+        <div class="form__error-msg error-msg--email"></div>
 
         <label for="nickname" class="form__label">닉네임</label>
         <input
@@ -37,6 +43,7 @@
           placeholder="닉네임을 입력해주세요"
           class="form__input"
         />
+        <div class="form__error-msg error-msg--nickname"></div>
 
         <label for="password" class="form__label">비밀번호</label>
         <div class="input--password">
@@ -45,50 +52,70 @@
             name="password"
             type="password"
             required
-            autocomplete="password"
+            autocomplete="off"
             placeholder="비밀번호를 입력해주세요"
             class="form__input"
           />
           <button
             type="button"
-            class="btn btn--visibility-off"
+            class="btn btn--visibility"
             aria-label="비밀번호 표시"
             aria-pressed="false"
           >
             <img
               src="assets/icons/btn_visibility_off.svg"
               alt="비밀번호를 보이지 않게끔 설정하는 눈에 빗금이 쳐진 아이콘입니다."
-              class="form__img"
+              class="form__icon"
+            />
+            <img
+              src="assets/icons/btn_visibility_on.svg"
+              alt="비밀번호를 보이게끔 설정하는 눈 모양의 아이콘입니다."
+              class="form__icon display-none"
             />
           </button>
         </div>
+        <div class="form__error-msg error-msg--password"></div>
 
-        <label for="password" class="form__label">비밀번호 확인</label>
+        <label for="password-confirm" class="form__label">비밀번호 확인</label>
         <div class="input--password">
           <input
-            id="password"
-            name="password"
+            id="password-confirm"
+            name="password-confirm"
             type="password"
             required
-            autocomplete="password"
+            autocomplete="off"
             placeholder="비밀번호를 재입력해주세요"
             class="form__input"
           />
           <button
             type="button"
-            class="btn btn--visibility-off"
+            class="btn btn--visibility"
             aria-label="비밀번호 표시"
             aria-pressed="false"
           >
             <img
               src="assets/icons/btn_visibility_off.svg"
               alt="비밀번호를 보이지 않게끔 설정하는 눈에 빗금이 쳐진 아이콘입니다."
-              class="form__img"
+              class="form__icon"
+            />
+            <img
+              src="assets/icons/btn_visibility_on.svg"
+              alt="비밀번호를 보이게끔 설정하는 눈 모양의 아이콘입니다."
+              class="form__icon display-none"
             />
           </button>
         </div>
+        <div class="form__error-msg error-msg--password-confirm"></div>
 
-        <button type="submit" class="btn btn--interactions">회원가입</button>
+        <!-- onclick 부분은 form제출 기능이 있다면 추후 변경 -->
+        <button
+          type="submit"
+          onclick="location.href='login.html'; return false;"
+          disabled
+          class="btn btn--interactions btn--disabled"
+        >
+          회원가입
+        </button>
       </form>
       <div class="container container--easy-login">
         간편 로그인하기
@@ -116,5 +143,6 @@
         이미 회원이신가요? <a class="text--url" href="login.html">로그인</a>
       </div>
     </main>
+    <script type="module" defer src="js/login-signup.js"></script>
   </body>
 </html>