diff --git a/Cargo.lock b/Cargo.lock
index fe3065e0..21157be4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -328,7 +328,6 @@ dependencies = [
  "hex-literal",
  "hmac",
  "password-hash",
- "rayon",
  "sha1",
  "sha2",
  "streebog",
@@ -518,9 +517,18 @@ checksum = "5a5f39404a5da50712a4c1eecf25e90dd62b613502b7e925fd4e4d19b5c96512"
 
 [[package]]
 name = "wasi"
-version = "0.14.4+wasi-0.2.4"
+version = "0.14.5+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4494f6290a82f5fe584817a676a34b9d6763e8d9d18204009fb31dceca98fd4"
+dependencies = [
+ "wasip2",
+]
+
+[[package]]
+name = "wasip2"
+version = "1.0.0+wasi-0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88a5f4a424faf49c3c2c344f166f0662341d470ea185e939657aaff130f0ec4a"
+checksum = "03fa2761397e5bd52002cd7e73110c71af2109aca4e521a9f40473fe685b0a24"
 dependencies = [
  "wit-bindgen",
 ]
diff --git a/pbkdf2/CHANGELOG.md b/pbkdf2/CHANGELOG.md
index 179287cd..d6cfb643 100644
--- a/pbkdf2/CHANGELOG.md
+++ b/pbkdf2/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## 0.13.0 (UNRELEASED)
+### Removed
+- The `parallel` crate feature  ([#702])
+
+[#702]: https://github.com/RustCrypto/password-hashes/pull/702
+
 ## 0.12.2 (2023-07-08)
 ### Fixed
 - Use `RECOMMENDED_ROUNDS` in `Default` impl for `Params` ([#442])
diff --git a/pbkdf2/Cargo.toml b/pbkdf2/Cargo.toml
index 230a802d..7da80e40 100644
--- a/pbkdf2/Cargo.toml
+++ b/pbkdf2/Cargo.toml
@@ -17,7 +17,6 @@ rust-version = "1.85"
 digest = { version = "0.11.0-rc.1", features = ["mac"] }
 
 # optional dependencies
-rayon = { version = "1.7", optional = true }
 password-hash = { version = "0.6.0-rc.0", default-features = false, optional = true, features = ["rand_core"] }
 hmac = { version = "0.13.0-rc.1", default-features = false, optional = true }
 sha1 = { version = "0.11.0-rc.2", default-features = false, optional = true }
@@ -34,8 +33,6 @@ belt-hash = "0.2.0-rc.1"
 [features]
 default = ["hmac"]
 std = ["password-hash/os_rng"]
-
-parallel = ["rayon", "std"]
 simple = ["hmac", "password-hash", "sha2"]
 
 [package.metadata.docs.rs]
diff --git a/pbkdf2/src/lib.rs b/pbkdf2/src/lib.rs
index 6550061a..65c864d7 100644
--- a/pbkdf2/src/lib.rs
+++ b/pbkdf2/src/lib.rs
@@ -3,11 +3,18 @@
 //!
 //! # Examples
 //!
-//! PBKDF2 is defined in terms of a keyed pseudo-random function (PRF). Most
-//! commonly HMAC is used as this PRF. In such cases you can use [`pbkdf2_hmac`]
-//! and [`pbkdf2_hmac_array`] functions. The former accepts a byte slice which
-//! gets filled with generated key, while the latter returns an array with
-//! generated key of requested length.
+//! PBKDF2 is defined in terms of a keyed pseudo-random function (PRF).
+//! The most commonly used PRF for this purpose is HMAC. In such cases
+//! you can use [`pbkdf2_hmac`] and [`pbkdf2_hmac_array`] functions.
+//! The former accepts a byte slice which gets filled with generated key,
+//! while the latter returns an array with generated key of requested length.
+//!
+//! Note that it is not recommended to generate keys using PBKDF2 that exceed
+//! the output size of the PRF (equal to the hash size in the case of HMAC).
+//! If you need to generate a large amount of cryptographic material,
+//! consider using a separate [key derivation function][KDF].
+//!
+//! [KDF]: https://github.com/RustCrypto/KDFs
 //!
 //! ```
 //! # #[cfg(feature = "hmac")] {
@@ -96,9 +103,6 @@ pub use hmac;
 #[cfg(feature = "simple")]
 pub use crate::simple::{Algorithm, Params, Pbkdf2};
 
-#[cfg(feature = "parallel")]
-use rayon::prelude::*;
-
 use digest::{FixedOutput, InvalidLength, KeyInit, Update, typenum::Unsigned};
 
 #[cfg(feature = "hmac")]
@@ -162,21 +166,10 @@ where
     PRF: KeyInit + Update + FixedOutput + Clone + Sync,
 {
     let n = PRF::OutputSize::to_usize();
-    // note: HMAC can be initialized with keys of any size,
-    // so this panic never happens with it
     let prf = PRF::new_from_slice(password)?;
 
-    #[cfg(not(feature = "parallel"))]
-    {
-        for (i, chunk) in res.chunks_mut(n).enumerate() {
-            pbkdf2_body(i as u32, chunk, &prf, salt, rounds);
-        }
-    }
-    #[cfg(feature = "parallel")]
-    {
-        res.par_chunks_mut(n).enumerate().for_each(|(i, chunk)| {
-            pbkdf2_body(i as u32, chunk, &prf, salt, rounds);
-        });
+    for (i, chunk) in res.chunks_mut(n).enumerate() {
+        pbkdf2_body(i as u32, chunk, &prf, salt, rounds);
     }
 
     Ok(())