diff --git a/EESSI-install-software.sh b/EESSI-install-software.sh
index 8dc0663e..a7ae9601 100755
--- a/EESSI-install-software.sh
+++ b/EESSI-install-software.sh
@@ -436,6 +436,37 @@ else
             echo_green "All set, let's start installing some software with EasyBuild v${eb_version} in ${EASYBUILD_INSTALLPATH}..."
 
             if [ -f ${easystack_file} ]; then
+                if [ -z $EESSI_SKIP_FETCH_EASYSTACK_SOURCES ]; then
+                    # run eb --help to determine if --fetch-all is supported (available since 5.3.0), otherwise fall back to --fetch
+                    fetch_option="--fetch"
+                    ${EB} --help | grep -q -e "fetch-all" && fetch_option="--fetch-all"
+                    easystack_additions=$(mktemp --suffix=.yml)
+                    # use the PR diff file to find which items have been added to this particular easystack file
+                    # and dump that to a temporary easystack file that we can use to fetch the sources for only these added items
+                    awk -v file="${easystack_file}" '
+                        /^diff --git / { found=0 }
+                        $0 == "+++ b/" file { found=1; next }
+                        found && /^\+/ && !/^\+\+\+/ {
+                            sub(/^\+/, "")
+                            additions = additions $0 "\n"
+                            count++
+                        }
+                        END {
+                            if (count)
+                                printf "easyconfigs:\n%s", additions
+                            else
+                                print "easyconfigs: []"
+                        }
+                    ' "${diff_file}" >> ${easystack_additions}
+                    echo_green "Downloading sources for added items in easystack file ${easystack_file} using eb ${fetch_option}..."
+                    echo '(note: this step can be skipped by setting $EESSI_SKIP_FETCH_EASYSTACK_SOURCES to a non-empty value)'
+                    ${EB} ${fetch_option} --easystack ${easystack_additions} --robot
+                    if [ $? -ne 0 ]; then
+                        fatal_error "Could not download all required source files for this easystack file."
+                    fi
+                    rm ${easystack_additions}
+                fi
+
                 echo_green "Feeding easystack file ${easystack_file} to EasyBuild..."
 
                 if [[ ${easystack_file} == *"/rebuilds/"* ]]; then