The Big Bang Theory Wiki

This chronology is a timeline of events that happened before The Big Bang Theory began.



  • May 7, 1974: Stuart is born
  • December 17, 1979: Amy Farrah Fowler is born


  • February 26, 1980: Sheldon and Missy are born
  • May 17, 1980: Leonard is born
  • March–September 1981: Howard is born
  • October 6, 1981: Raj is born
  • 1985: Sheldon's grandfather, Pop-Pop, dies
  • December 2, 1985: Penny is born
  • June 23, Between 1984 and 1987: Bernadette is born
  • 1986-1987: Leonard, six years old at the time, walks in on his naked parents and his mother is swatting his father with Leonard's new ping-pong paddle.
  • 1989: Sheldon starts high school at the age of 9.


  • 1991: Sheldon starts college at age 11
  • 1992: Sheldon takes engineering class with Professor Boucher.
  • 1992: At age 12, Sheldon does a series of experiments involving the height of stairs and increased the heights of stairs by 2 millimeters and as a result, his father tripped and broke his clavicle.
  • 1993: Sheldon and his father watch the 1993 Thanksgiving Game in Dallas, and his father gets so angry with the results that he shoots the television.
  • 1995: Sheldon attends Comic-Con to meet Wil Wheaton; when Wil doesn't show up, this fuels Sheldon's longtime hatred for him.
  • 1996: Sheldon receives his doctorate.
  • 1997-1998: Penny rebuilds a tractor engine all by herself at age 12


  • Sometime this decade: Stuart came to Pasadena and opened up the Comic Book Store.
  • 2000: Amy begins training in the field of neurobiology
  • 2003: Sheldon and Leonard meet for the first time; the duo also meet Howard and Raj
  • 2003: The Elevator to the Apartment Building is destroyed
  • 2004: Leonard earns his doctorate and officially becomes a doctor.
  • 2003-2007: Penny moves to Pasadena, starts dating Kurt, and gets a job at The Cheesecake Factory
  • September 22, 2007: Leonard and Raj created an idea involving the conversion of footsteps into electromagnetic energy to make it possible for one to recharge their cell phone while walking.
  • Before September 24, 2007: Penny breaks up with Kurt.

March 10, 1919: Amy’s Aunt Flora born (S05E19: The Weekend Vortex).[]

December 28, 1922: Stan Lee born (S03E16: The Excelsior Acquisition).[]

February 22, 1929: Chen, later manager of Szechwan Palace, born (S01E07: The DumplingParadox,  S01E17: The Tangerine Factor).[]

September 5, 1929 Dr. Arthur Jeffries aka Professor Proton born [The Proton Resurgence, The Proton Displacement][]

January 17, 1931 James Earl Jones born [The Convention Conundrum]

January 31, 1941 Mrs. Latham born [The Benefactor Factor]

February 20, 1945 George Smoot born [The Terminator Decoupling]

August 30, 1948  Dr. Crawley, later an etymologist born [The Jiminy Conjecture]  []

February 2, 1949 Brent Spiner born [The Russian Rocket Reaction]

August 8, 1949 Wyatt, Penny's dad is born [The Boyfriend Complexity]

August 11, 1950 Steve Wozniak born [The Cruciferous Vegetable Amplification]

June 5, 1951 Dr. Eric Gablehouser born 

February 2, 1952 Mrs. Wolowitz, Howard's mother born

May 2, 1952  Dr. Beverly Hofstadter born 

July 1, 1952 Dr. V.M. Koothrappali born 

January 14, 1954 Althea, a nurse born [The Werewolf Transformation and The Robotic Manipulation]

May 16, 1954 Angelo, the nephew of Sheldon's barber born [The Werewolf Transformation]

February 24, 1955 Steve Jobs born

June 16, 1955 Mary Cooper born 

November 27, 1955 Bill Nye born [The Proton Displacement]

November 29, 1955 Howie Mandel born [The Re-Entry Minimization]

July 6, 1956 Mike Rostenkowski born

October 21, 1956 Carrie Fisher born [The Convention Conundrum]

February 16, 1957 LeVar Burton born [The Toast Derivation, The Habitation Configuration]

October 5, 1958 Neil de Grasse Tyson born [The Apology Insufficiency]

August 19, 1962 Mike Massimo born [The Friendship Contraction]

July 3, 1964 Sandy future CA employment services worker born [The Einstein Approximation]

September 3, 1965 Charlie Sheen born [The Griffin Equivalency]

January 17, 1966 President Siebert born [The Benefactor Factor]

July 6, 1966 Bert, who likes Amy born [The Occupation Recalibration]

February 16, 1967 Cosmonaut Dimitri Rezinov born [The Countdown Reflection]

July 24, 1969 Glenn Bernadette's former professor & boyfriend born [The Love Car Displacement]

June 22, 1970 Dr. David Underhill born [The Bath Item Gift Hypothesis]

January 15, 1971 Janine Davis, later Cal Tech's Human Resource Manager born

May 30, 1971 Barry Kripke, later a professor at Cal Tech born

July 29, 1972 Wil Wheaton born 

February, 1972 to February, 1973   Leonard's sister born [The Cohabitation Formulation]

1974 Stephen Hawking records a lecture at MIT [Pilot]

March, 1974 to May, 1975 Stuart Bloom born [The Stag Convergence]

September 18, 1974 Eric, who dated Penny born [The Codpiece Topology]

January 3, 1975 Abby, who dates Raj born [The Psychic Vortex]

January 29, 1975 Dr. Leslie Winkle born

July 20, 1975 Dr. Elizabeth Plimpton born [The Plimpton Stimulation]

May 13, 1977 Zack Johnson born

September 24, 1977 Dr. Catherine Millstone born [The Pirate Solution]

November, 1977 to November 1978 the Rostenkowskis get married [The Thanksgiving Decoupling]

March 3, 1978 Priya Koothrappali born 

June 10, 1978 Toby Loobenfeld, who impersonates Sheldon's cousin Leo born [The Loobenfeld Decay]

June 27, 1978 Alice, who later dates Leonard born [The Good Guy Fluctuation]     

January 26, 1979 Dr. Stephanie Barnett born [The Lizard-Spock Expansion, The White Asparagus Triangulation, The Vartabedian Conundrum]

March 5, 1979 Ramona Nowitzki born [The Cooper-Nowitzki Theorem]

March 31, 1980 Lucy, who later dates Raj is born

May 17, 1980 Leonard Hofstadter born [The Alien Parasite Hypothesis (12 years after High school] [The Peanut Reaction]

June 23, 1980 Bernadette Rostenkowski born 

November 25, 1980 Alicia born [The Dead Hooker Juxtaposition]

December 30, 1980 future FBI agent Angela Page born [The Apology Insufficiency]

March 14, 1981 Cole, who is in Penny's history class born [The 43 Peculiarity]

April 21 – May 21, 1981 Sheldon Cooper born

July 24, 1981 Summer Glau born [The Terminator Decoupling]

October 6, 1981 Rajesh Koothrappali born [The Grasshopper Experiment][The Prestidigitation Approximation]

February 17, 1982 Christy Vanderbel  is born [The Dumpling Paradox]

April, 1981 to December, 1981   Howard Wolowitz is born[The Pancake Batter Anomaly] [The Recombination Hypothesis]

August 24, 1984 Kevin who liked Penny born [The Ornithophobia Diffusion]

April, 1985 – May, 1986 Sheldon's mother tells him he can't point out to people that they are not as smart as him [The Luminous Fish Effect]

December 2, 1985 Penny born [The Barbarian Sublimation, The Prestidigitation Approximation]

March 4, 1986 Alex Jensen, later Dr. Sheldon Cooper's graduate assistant born

April, 1986 –May 1987 Sheldon starts carrying “Justice League of America” membership card in his wallet  [The grasshopper Experiment], Billy

Sparks shoves a Mexican peso up his nose [Shiny Trinket Maneuver] and his PopPop dies [The Santa Simulation] 

October 31, 1986 Howard has first anaphylactic shock [The Habitation Configuration]

November 6, 1986 Emily, who dated Raj born [The Wiggly Finger Catalyst]

November 10, 1986 Jesse, Stuart's rival born [The Occupation Recalibration]

December, 1986 Sheldon asks the Baybrook Mall Santa to bring his Pop Pop back [The Santa Simulation]

October 31, 1987 Sheldon dresses as Stephen Hawking for Halloween [The Hawking Excitation]

March 22, 1988  Yvette, later a vet born [The Locomotive Manipulation]

April, 1988 – May, 1989 Sheldon chased up tree by chicken [The Ornithophobia Diffusion] November 9, 1988  Annleigh Tipton born [The Panty Piñata Polarization]

1989 Sheldon starts his enemy list [The Russian Rocket Reaction]

March, 1989 Sheldon tries and fails to do a chin-up [The Thespian Catalyst]

April, 1989 – May 1990 Sheldon tries to convert Missy's ez Bake oven into a nuclear furnace [The Pork Chop Indeterminancy] and the Cooper's Cat 'Lucky' is run over by a Montgomery Ward delivery truck [The Griffin Equivilancy]

January 20, 1990 Samantha Potter born [The Panty Piñata Polarization]

April, 1991 and May, 1992 Sheldon writes “Where no Sheldon has gone before”  [The Thespian Catalyst] ,

Missy gets her father “A World’s Greatest Dad” coffee mug [The Griffin Equivalency]

Between Sept. 91 and May 92 Penny & Rosie make pact to marry Bert & Ernie [The Creepy Candy Coating Corollary]

April 1992 to February 1993 Howard's father leaves [The Precious Fragmentation] & he has a karate lesson [The Alien Parasite Hypothesis]

May, 1992 to May, 1993 Sheldon sends bag of excrement to FBI crime lab [The Apology Insufficiency]   

September, 1992 Sheldon starts college [The Hamburger Postulate]

September, 1992 to May, 1993 in seventh grade Leonard tries wearing contacts [The Zarnecki Incursion]

April, 1992 to March, 1993 Dennis Kim born [The Jerusalem Duality]

April 1992 – May, 1993 for 12th b-day Sheldon gets motorized dirt bike instead of titanium centrifuge  [The Peanut Reaction]

April, 1993 to May, 1994 while 12 Sheldon conducts staircase experiments [Pilot] magpie tries to steal Sheldon's retainer [The Ornithophobia Diffusion]

April, 1994 to May, 1995 Sheldon tries to build nuclear reactor & death ray [The Luminous fish effect]

April, 1994 to December, 1995 Howard takes a karate lesson [The Jiminy Conjecture]

April 21, 1995 to May 21, 1996, Sheldon's father dies [The Thanksgiving Decoupling]

May, 1995 Sheldon graduates sum cum laude from college as valedictorian [The Pants Alternative]

November 1995 Sheldon wins Stevenson award [The Jerusalem Duality]

1995 Sheldon attend Dixie Trek IV [The Creepy Candy Coating Corollary]

September, 1996 Sheldon starts year as guest lecturer at the Heidelberg Institute [The Pancake Batter Anomaly] & Howard meets Denise Palmari [The  

Jerusalem Duality]

April, 1996 Penny's nephew born [The Hofstadter Isotope]

April, 1997 – May, 1998 parrot calls Sheldon "fat ass" [The Ornithophobia Diffusion ]

May, 1998 Leonard Hofstadter graduates from high school [The Alien Parasite Hypothesis]

1999 Sheldon has pernicious anemia [The Codpiece Topology]

April, 1999 Sheldon starts on thesis [The Luminous Fish Effect]

April, 1998 to December, 1999 Howard's mom removes bed rail [The Countdown Reflection]

May, 1999 and May 2000 Sheldon moves into apartment [The Dumpling Paradox]  and Amy's cousin Irene and family die in a CO accident [The  

Isolation Permutation}

April, 2000 to May, 2001 Sheldon has full pubis [The Habitation configuration]

October - December 2002 Leonard moves in [The 21 Second Excitation, The Staircase Implementation] or beginning of 2003 [The 2003 Approximation]

December 12, 2002 Leonard & Sheldon stand in line 14 hours to see Star Trek: Nemesis [The 21 Second Excitation]

April, 2003 Sheldon finishes thesis, becomes PhD starts work at  Cal Tech [The Luminous Fish Effect]

May, 2003 Sheldon goes on cruise to the Arctic to see solar eclipse [The Hamburger Postulate], while Leonard dates a French PhD in French literature 

February, 2003 to February 2004 Penny starts living with Kurt [Pilot]

May, 2003 to October, 2003 Raj meets Howard [The Apology Insufficiency]

October, 2003 Howard meets Sheldon, then replaces slides in Sheldon's presentation [The Friendship Turbulence]

May, 2004 Leonard Hofstadter gets his doctorate in physics [The Cooper-Hofstadter Polarization]

June 30, 2004 at opening of Spiderman 2 Leonard & Howard make girlfriend pack [The Creepy Candy Coating Corollary]

April 12, 2005 Leonard & Howard make pinkie swear not to hit on Priya [The Irish Pub Formulation}

October, 2005 Leonard's rocket fuel accident wrecks elevator [The Nerdvana Annihilation]

April, 2006 to April, 2007 Penny and Kurt move to LA [The Barbarian Sublimation]

 2006   Sheldon has an ear infection [The Pancake Batter Anomaly] and Penny appears topless in Serial Apeist, a low budget horror film [The Hofstadter Insufficiency]

November 23, 2006 Leonard’s alzheimic grandmother has an episode and removes her clothing on Thanksgiving [Pilot]

July, 2007   Raj has an encounter with Richard at Comic-Con and Leonard meets a girl there   [The Codpiece Topology]

August 28, 2007   Leonard, Sheldon, Howard & Raj play Klingon boggle [Pilot]

September 22, 2007 Leonard, Sheldon, Howard & Raj invent a charging device powered by the energy generated while walking. Sheldon composed a Dr. Suess memorial poem.


It is assumed that is a character's birthdate has not been given they have the same birthdate as the actor who plays them. If some one says something happened six years ago they actually mean anywhere between 5 and a half and six and a half years ago.