diff --git a/halo2_proofs/Cargo.toml b/halo2_proofs/Cargo.toml
index f82e03a5..6368bddc 100644
--- a/halo2_proofs/Cargo.toml
+++ b/halo2_proofs/Cargo.toml
@@ -67,6 +67,11 @@ gumdrop = "0.8"
 proptest = "1"
 rand_core = { version = "0.6", default-features = false, features = ["getrandom"] }
 
+# Indirect dev-dependencies that we pin to preserve MSRV in CI checks.
+dashmap = ">=5, <5.5.0" # dashmap 5.5.0 has MSRV 1.64
+image = ">=0.24, <0.24.5" # image 0.24.5 has MSRV 1.61
+tempfile = ">=3, <3.7.0" # tempfile 3.7.0 has MSRV 1.63
+
 [target.'cfg(all(target_arch = "wasm32", target_os = "unknown"))'.dev-dependencies]
 getrandom = { version = "0.2", features = ["js"] }