| Character | First appearance | Description |
| Dick Grayson | Detective Comics #38 | Serving with Wally West on the Teen Titans, Grayson would become West's best friend and act as best man at his wedding. |
| Iris West | Showcase #4 | A reporter and Barry Allen's girlfriend and eventual wife. |
| Ira West | Flash #134 | Iris's father and Wally's grandfather who is a bit of an absent minded professor. |
| Rudy West | Flash #116 | Wally's father, Iris's brother and Ira's son. Eventually revealed to be working for the Manhunters. |
| Henry Allen | Flash #126 | Barry Allen's father. He's a doctor. |
| Nora Allen | Flash #126 | Barry Allen's mother. |
| Solovar | Flash #106 | The king of Gorilla City for much of the dealings the Flash had with the culture. |
| Hal Jordan | Showcase #22 | Served with the Flash in the JLA where the unlikely pair became best friends. |
| Justice League of America | The Brave and the Bold #28 | Group of costumed heroes that protected the world against some of its worst threats. Barry Allen was a founding member. |
| Elongated Man | Flash #112 | A super hero and ally of the Flash who operated out of Central City. |
| Sue Dibny | Flash #119 | A socialite who dated and later married Elongated Man. |
| Daphne Dean | Flash #126 | An actress who grew up with and dated Barry Allen. |
| Mary West | Flash #133 | The mother of Wally West who moved in with him for a time. |
| Dexter Myles | Flash #138 | The curator of the Flash Museum. |
| Doralla Kon | Flash #145 | An alien from the planet Alkomar who arrived on Earth to learn while there she has super-speed. |
| Teen Titans | The Brave and the Bold #54 | A group that began as a team of sidekicks for the JLA and grew into a home for teen heroes. Wally West was a founding member. |
| Tornado Twins | Adventure Comics #373 | Don and Dawn Allen, twin son and daughter of Barry and Iris Allen who became heroes in the 30th century with their children Bart Allen and XS. |
| Character | First appearance | Description |
| Pied Piper | Flash #106 | A longtime member of the Rogues who later reforms and becomes Wally West's ally. |
| Fiona Webb | Flash #285 | A woman who dated and nearly married Barry Allen. On their wedding day, the Reverse-Flash masqueraded as the hero and nearly killed Webb, instead being killed himself by the Flash. Webb would suffer nervous breakdowns afterward at even the mention of Allen's name. |
| Patty Spivot | 5-Star Super-Hero Spectacular | Barry Allen's assistant in the police lab. |
| Matthew Paulson | Flash #273 | A corrupt police chief who was Barry Allen's supervisor prior to Darryl Frye. |
| Darryl Frye | Flash #285 | A police captain for the Central City Police Department and Barry Allen's direct superior. In The New 52, Frye is Barry's foster father. |
| Frank Curtis | Flash #270 | A detective for the Central City Police Department and Barry Allen's friend. |
| Mack Nathan | Flash #285 | Mack is Barry Allen's African American neighbor and friend. His son Troy Nathan lives with him. |
| Cecile Horton | Flash #332 | Barry Allen's lawyer during his murder trial. |
| Cyborg | DC Comics Presents #26 | A close friend Wally West made from the Teen Titans. |
| Raven | DC Comics Presents #26 | Wally West had a crush on Raven which she used her magic to manipulate him to rejoin the Teen Titans. However, she would begin to have feelings for him which threatened to unleash the evil inside her. |
| Magenta | The New Teen Titans #17 | Wally West's girlfriend while he was Kid Flash, when he learned she could manipulate magnetism he tried to force her into becoming a super-hero. However, it instead pushed her growing mental illness into bipolar disorder. She would often be manipulated into acting as a super-villain and other times take part in destructive behavior on her own. |
| Connie Noleski | Flash Annual #1 | A model who had an on-and-off again relationship with Wally West. She later dated and became engaged to Chunk. |
| Tina McGee | Flash #3 | A scientist who studied Wally West and dated him for a time. She would reunite with her estranged husband and the pair work together for S.T.A.R. Labs. |
| Jerry McGee | Flash #5 | Tina McGee's husband and a scientist researching how to enhance the human body. Performing tests on himself, he turned himself into a super-villain known as Speed McGee and Speed Demon. The Flash helped him get treatment and Jerry reconnected with his wife. |
| Red Trinity | Flash #6 | A trio of super-heroes from Russia that formed the service Kapitalist Kouriers in the US. Their predecessor was Blue Trinity. |
| Lady Flash | Flash ##7 | Formerly Christina of Blue Trinity, Vandal Savage made the villainess his slave via an addiction to cocaine and gave her a spare Flash costume wherein she took up the title "Lady Flash". When Savage ordered her to kill the Flash, she refused and joined the hero in taking the villain down. When Christina asked to become the Flash's partner however, he refused. |
| Chunk | Flash #9 | A scientist who developed a long range teleportation device and, in an accident, merged with it. Forced to absorb mass such that his invention does not consume him, Chunk ran afoul of the Flash when these acts caused chaos. With the hero's help, Chunk was able to get his abilities under control, opening a waste removal business, and became a close friend to Wally West. |
| Mason Trollbridge | Flash #15 | Once the sidekick to the vigilante the Clipper, Trollbridge was a neighbor to Wally West in New York, later becoming his friend. At one point, Trollbridge took up the mantle of the Clipper and his son became the supervillain Last Resort. |
| Linda Park | Flash #28 | A reporter who dated and eventually married Wally West. They have two children, Iris and Jai. |
| Character | First appearance | Description |
| Max Mercury | National Comics #5 | A US Cavalry scout empowered by a Native American shaman with super-speed, Max Mercury is considered one of the foremost experts in the Speed Force. He bounced through time entering the force, appearing throughout history and mentoring speedsters. |
| Trickster | The Flash #113 | One of the Flash's most consistent rogues, the Trickster was brainwashed by the Top and joined the FBI. Trickster would later form a group of reformed Flash rogues to topple his current ranks of enemies until the Top removed his influence. |
| Top | The Flash #122 | One of the Flash's rogues, the Top was magically brainwashed by Zatanna into becoming a hero and would briefly be the Flash's partner. Unfortunately, his new programming clashed with his guilt over his past and he lost his mind. The Top would brainwash the Trickster, Pied Piper, and Heat Wave. |
| Heat Wave | The Flash #140 | One of the Flash's rogues, Heat Wave was brainwashed by the Top into becoming a hero and worked for Project Cadmus. He would end up at the FBI under the Trickster beside other reformed rogues before the Top removed his influence. |
| Keith Kenyon | Green Lantern #38 | Formerly an enemy of the Green Lantern as Goldface, Kenyon reformed and became a Union boss in Keystone City. |
| Jesse Quick | Justice Society of America #1 | The daughter of Johnny Quick and Liberty Belle, Jesse for a time acted as the Flash's partner and agreed to be his successor. |
| Argus | The Flash Annual #6 | A federal agent who gained super powers, Argus became a hero and ally to the Flash in Central City. |
| Green Lantern | Green Lantern #48 | Serving with Wally West in the JLA, the duo clashed but eventually became good friends. |
| XS | Legionnaires #0 | The granddaughter of Barry Allen and daughter of Dawn Allen of the Tornado Twins. |
| Preston Lindsay | Impulse #1 | The best friend of Bart Allen when he lived in Manchester, Alabama. |
| Carol Bucklen | Impulse #4 | Bart Allen's first love, who went to the future with him when Max Mercury was believed dead. |
| Mister Terrific | Spectre #54 | Fellow Justice Leaguer and the third-smartest man in the world, who employs Wally West at his company Terrifitech. |
| Arrowette | Impulse #28 | The daughter of Miss Arrowette, Arrowette was a hero in Manchester where she befriended Bart Allen. |
| Young Justice | Young Justice: The Secret #1 | Largely made up of a new, younger generation of sidekicks to the JLA, Bart Allen was a founding member of the group. |
| Justice Legion Alpha | DC One Million #1 | The premier super hero team of the 853rd century, a time-traveling John Fox became that generation's Flash. |
| Angela Margolin | The Flash #143 | A scientist who took over Barry Allen's position in the Central City police department after his absence. She would become romantically involved with the Dark Flash. |
| Fred Chyre | The Flash #170 | Detective for the Keystone City police. |
| Jared Morillo | The Flash #171 | A detective for the Keystone City police and Fred Chyre's partner for the Department of Metahuman Hostility. After a battle with the villain Cicada, Morillo develops an advanced healing factor that renders him nigh-immortal. |
| Gregory Wolfe | The Flash: Iron Heights | The warden of Iron Heights. He seems to have no tolerance for his inmates and is able to cause pain or comfort in others using his mind. |
| Hunter Zolomon | The Flash: Secret Files & Origins #3 | A talented former profiler for the FBI specializing in super-villains who became an asset for the Keystone City police. After being paralyzed from the waist down by Gorilla Grodd, Zolomon asked the Flash to go back in time and fix the agent's life. Zolomon attempted to use the Cosmic Treadmill to go back in time himself but instead resulted in an accident turning him into the villain Zoom. |
| Peek-a-Boo | The Flash #180 | A youth with the power to teleport, Lashawna Baez attempted to use her powers to steal a kidney for her ailing father. While she would be caught and battle the Flash again, she admitted she idolized the hero and wanted to also be a hero. |
| Ashley Zolomon | The Flash #197 | The ex-wife of Hunter Zolomon, Ashley blamed herself for his transformation into Zoom. She took his place as the police's profiler in hopes Hunter could one day be rehabilitated. |
| David Singh | The Flash ''Secret Files and Origins #2010 | Barry's CCPD Crime Lab supervisor. |
| James Forrest | The Flash: Rebirth #2 | Scientist at the Central City Crime Lab. |
| Kristen Kramer | The Flash Secret Files and Origins #2010 | Intern at the Central City Crime Lab. |
| Owen Mercer | Identity Crisis #3 | The son of Captain Boomerang and half-brother of Bart Allen, Mercer largely has walked a fine line between hero and villain. He would join the Suicide Squad and helped apprehend the Rogues who killed Bart Allen. |
| Irey West | The Flash #225 | Twins of Wally West and Linda Park raised in the Speed Force, with Jai getting super-strength and Iris getting speed powers. Also known as the modern "Tornado Twins". |
| Jai West | The Flash #225 | Twins of Wally West and Linda Park raised in the Speed Force, with Jai getting super-strength and Iris getting speed powers. Also known as the modern "Tornado Twins". |
| Valerie Perez | The Flash: The Fastest Man Alive #1 | The daughter of Manfred Mota, Perez was once saved by Bart Allen and she would dedicate her life to studying the Speed Force. Studying him as an intern at S.T.A.R. Labs, the two would begin a romantic relationship. She would hold him in her arms as he died from his injuries at the hands of the Rogues. |
| The Renegades | The Flash #1 | A police task force from the 25th century who believed Barry Allen murdered team member Mirror Monarch. |
| Wade West | The Flash #798 | Third child of Wally West and Linda Park, whose connection to the Speed Force was imbued in Linda while she was pregnant. |
| Foxy | The Flash'' #13
| The dog-like offspring of the Deep Change, the embodiment of time. Foxy emanates Speed Force energy, allowing speedsters near him to maintain their powers even if they are drained. |