diff --git a/src/builtin_bg.cpp b/src/builtin_bg.cpp
index 9af0cbbfc..e737edae4 100644
--- a/src/builtin_bg.cpp
+++ b/src/builtin_bg.cpp
@@ -52,7 +52,7 @@ int builtin_bg(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
     if (optind == argc) {
         // No jobs were specified so use the most recent (i.e., last) job.
         job_t *job = nullptr;
-        for (auto j : jobs()) {
+        for (const auto &j : jobs()) {
             if (j->is_stopped() && j->get_flag(job_flag_t::JOB_CONTROL) && (!j->is_completed())) {
                 job = j.get();
                 break;
diff --git a/src/builtin_disown.cpp b/src/builtin_disown.cpp
index dc766cc34..ad965b693 100644
--- a/src/builtin_disown.cpp
+++ b/src/builtin_disown.cpp
@@ -65,7 +65,7 @@ int builtin_disown(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
         // Foreground jobs can be disowned.
         // Even jobs that aren't under job control can be disowned!
         job_t *job = nullptr;
-        for (auto j : jobs()) {
+        for (const auto &j : jobs()) {
             if (j->is_constructed() && (!j->is_completed())) {
                 job = j.get();
                 break;
@@ -104,7 +104,7 @@ int builtin_disown(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
         }
 
         // Disown all target jobs
-        for (auto j : jobs) {
+        for (const auto &j : jobs) {
             retval |= disown_job(cmd, parser, streams, j);
         }
     }
diff --git a/src/builtin_fg.cpp b/src/builtin_fg.cpp
index befff322c..5bd9221b6 100644
--- a/src/builtin_fg.cpp
+++ b/src/builtin_fg.cpp
@@ -38,7 +38,7 @@ int builtin_fg(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
         // Select last constructed job (i.e. first job in the job queue) that can be brought
         // to the foreground.
 
-        for (auto j : jobs()) {
+        for (const auto &j : jobs()) {
             if (j->is_constructed() && (!j->is_completed()) &&
                 ((j->is_stopped() || (!j->is_foreground())) &&
                  j->get_flag(job_flag_t::JOB_CONTROL))) {
diff --git a/src/builtin_jobs.cpp b/src/builtin_jobs.cpp
index c3673b89d..f4dab2411 100644
--- a/src/builtin_jobs.cpp
+++ b/src/builtin_jobs.cpp
@@ -174,7 +174,7 @@ int builtin_jobs(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
 
     if (print_last) {
         // Ignore unconstructed jobs, i.e. ourself.
-        for (auto j : jobs()) {
+        for (const auto &j : jobs()) {
             if (j->is_constructed() && !j->is_completed()) {
                 builtin_jobs_print(j.get(), mode, !streams.out_is_redirected, streams);
                 return STATUS_CMD_ERROR;
@@ -215,7 +215,7 @@ int builtin_jobs(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
                 }
             }
         } else {
-            for (auto j : jobs()) {
+            for (const auto &j : jobs()) {
                 // Ignore unconstructed jobs, i.e. ourself.
                 if (j->is_constructed() && !j->is_completed()) {
                     builtin_jobs_print(j.get(), mode, !found && !streams.out_is_redirected, streams);
diff --git a/src/builtin_wait.cpp b/src/builtin_wait.cpp
index 34a687bb1..6df0d3abf 100644
--- a/src/builtin_wait.cpp
+++ b/src/builtin_wait.cpp
@@ -16,7 +16,7 @@
 /// If a specified process has already finished but the job hasn't, parser_t::job_get_from_pid()
 /// doesn't work properly, so use this function in wait command.
 static job_id_t get_job_id_from_pid(pid_t pid) {
-    for (auto j : jobs()) {
+    for (const auto &j : jobs()) {
         if (j->pgid == pid) {
             return j->job_id;
         }
@@ -31,7 +31,7 @@ static job_id_t get_job_id_from_pid(pid_t pid) {
 }
 
 static bool all_jobs_finished() {
-    for (auto j : jobs()) {
+    for (const auto &j : jobs()) {
         // If any job is not completed, return false.
         // If there are stopped jobs, they are ignored.
         if (j->is_constructed() && !j->is_completed() && !j->is_stopped()) {
@@ -48,7 +48,7 @@ static bool any_jobs_finished(size_t jobs_len) {
     if (jobs_len != jobs().size()) {
         return true;
     }
-    for (auto j : jobs()) {
+    for (const auto &j : jobs()) {
         // If any job is completed, return true.
         if (j->is_constructed() && (j->is_completed() || j->is_stopped())) {
             return true;
@@ -139,7 +139,7 @@ static bool match_pid(const wcstring &cmd, const wchar_t *proc) {
 static bool find_job_by_name(const wchar_t *proc, std::vector<job_id_t> &ids) {
     bool found = false;
 
-    for (const auto j : jobs()) {
+    for (const auto &j : jobs()) {
         if (j->command_is_empty()) continue;
 
         if (match_pid(j->command(), proc)) {
diff --git a/src/parse_execution.cpp b/src/parse_execution.cpp
index 8bd145c77..2af130d63 100644
--- a/src/parse_execution.cpp
+++ b/src/parse_execution.cpp
@@ -785,7 +785,7 @@ parse_execution_result_t parse_execution_context_t::populate_plain_process(
     static uint32_t last_exec_run_counter =  -1;
     if (process_type == process_type_t::exec && shell_is_interactive()) {
         bool have_bg = false;
-        for (const auto bg : jobs()) {
+        for (const auto &bg : jobs()) {
             // The assumption here is that if it is a foreground job,
             // it's related to us.
             // This stops us from asking if we're doing `exec` inside a function.
diff --git a/src/parser.cpp b/src/parser.cpp
index d6751dac0..4b0a75082 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -597,7 +597,7 @@ job_t *parser_t::job_get_from_pid(pid_t pid) const {
         return 0;
     }
 
-    for (auto job : jobs()) {
+    for (const auto &job : jobs()) {
         if (job->pgid == pgid) {
             for (const process_ptr_t &p : job->processes) {
                 if (p->pid == pid) {
diff --git a/src/proc.cpp b/src/proc.cpp
index 1530cdb9c..cc4705ffb 100644
--- a/src/proc.cpp
+++ b/src/proc.cpp
@@ -107,7 +107,7 @@ void job_t::promote() {
 }
 
 void proc_destroy() {
-    for (const auto job : jobs()) {
+    for (const auto &job : jobs()) {
         debug(2, L"freeing leaked job %ls", job->command_wcstr());
     }
     jobs().clear();
@@ -372,7 +372,7 @@ static void process_mark_finished_children(bool block_ok) {
 
     // We got some changes. Since we last checked we received SIGCHLD, and or HUP/INT.
     // Update the hup/int generations and reap any reapable processes.
-    for (const auto j : jobs()) {
+    for (const auto &j : jobs()) {
         for (const auto &proc : j->processes) {
             if (auto mtopic = j->reap_topic_for_process(proc.get())) {
                 // Update the signal hup/int gen.
@@ -645,7 +645,7 @@ unsigned long proc_get_jiffies(process_t *p) {
 
 /// Update the CPU time for all jobs.
 void proc_update_jiffies() {
-    for (auto job : jobs()) {
+    for (const auto &job : jobs()) {
         for (process_ptr_t &p : job->processes) {
             gettimeofday(&p->last_time, 0);
             p->last_jiffies = proc_get_jiffies(p.get());
@@ -880,7 +880,7 @@ void job_t::continue_job(bool send_sigcont) {
 void proc_sanity_check() {
     const job_t *fg_job = NULL;
 
-    for (const auto j : jobs()) {
+    for (const auto &j : jobs()) {
         if (!j->is_constructed()) continue;
 
         // More than one foreground job?
@@ -937,7 +937,7 @@ void proc_wait_any() {
 }
 
 void hup_background_jobs() {
-    for (auto j : jobs()) {
+    for (const auto &j : jobs()) {
         // Make sure we don't try to SIGHUP the calling builtin
         if (j->pgid == INVALID_PID || !j->get_flag(job_flag_t::JOB_CONTROL)) {
             continue;
diff --git a/src/reader.cpp b/src/reader.cpp
index e2c072700..6ffd3da31 100644
--- a/src/reader.cpp
+++ b/src/reader.cpp
@@ -2229,7 +2229,7 @@ void reader_bg_job_warning() {
     std::fputws(_(L"There are still jobs active:\n"), stdout);
     std::fputws(_(L"\n   PID  Command\n"), stdout);
 
-    for (auto j : jobs()) {
+    for (const auto &j : jobs()) {
         if (!j->is_completed()) {
             std::fwprintf(stdout, L"%6d  %ls\n", j->processes[0]->pid, j->command_wcstr());
         }
@@ -2253,7 +2253,7 @@ static void handle_end_loop() {
         }
 
         bool bg_jobs = false;
-        for (const auto j : jobs()) {
+        for (const auto &j : jobs()) {
             if (!j->is_completed()) {
                 bg_jobs = true;
                 break;