diff --git a/.github/r-ci.sh b/.github/r-ci.sh
index 2f0aad269b..4284c689fb 100755
--- a/.github/r-ci.sh
+++ b/.github/r-ci.sh
@@ -21,7 +21,7 @@ ARCH=$(uname -m)
 
 # Default CRAN repo (use the CDN) and R verssion
 CRAN=${CRAN:-"https://cloud.r-project.org"}
-RVER=${RVER:-"4.5.1"}
+RVER=${RVER:-"4.6.0"}
 
 ## Optional drat repos, unset by default
 DRAT_REPOS=${DRAT_REPOS:-""}
@@ -215,7 +215,7 @@ BootstrapLinuxOptions() {
 
 BootstrapMac() {
     # Install from latest CRAN binary build for OS X (given ${ARCH} from 'uname -m')
-    wget ${CRAN}/bin/macosx/big-sur-${ARCH}/base/R-${RVER}-${ARCH}.pkg  -O /tmp/R-latest.pkg
+    wget ${CRAN}/bin/macosx/sonoma-${ARCH}/base/R-${RVER}-${ARCH}.pkg  -O /tmp/R-latest.pkg
 
     echo "Installing macOS binary package for R on ${ARCH}"
     sudo installer -pkg "/tmp/R-latest.pkg" -target /
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 486c2085d1..30868b57db 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -15,7 +15,10 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - {os: macOS-latest, r: '4.5.1' }
+          - {os: macOS-latest, r: '4.6.0' }
+          # The value of `r` for Ubuntu is a placeholder that has no effect. R
+          # is installed from r2u via APT, and thus corresponds to the current
+          # release version
           - {os: ubuntu-latest, r: 'release'}
 
     runs-on: ${{ matrix.os }}