The following is a list of all team-to-team transactions that have occurred in the National Hockey League during the 1978–79 NHL season. It lists what team each player has been traded to, signed by, or claimed by, and for which player(s) or draft pick(s), if applicable.
| May 11, 1978 | To Cleveland Barons Fred Ahern | To Colorado Rockies cash | |
| May 15, 1978 | To Toronto Maple Leafs cash future considerations1 (rights to Owen Lloyd) | To Minnesota North Stars Jim McKenny | |
| May 30, 1978 | To Toronto Maple Leafs Bob Neely | To Colorado Rockies cash |
| June 2, 1978 | To Philadelphia Flyers 1st-rd pick - 1978 Amateur Draft (# 7 - Ken Linseman) | To New York Rangers rights to hire Fred Shero as new Rangers head coach | |
| June 12, 1978 | To Vancouver Canucks 4th-rd pick - 1978 Amateur Draft (# 56 - Harald Luckner) future considerations | To St. Louis Blues Mike Walton | |
| June 13, 1978 | To Toronto Maple Leafs Dave Burrows 6th-rd pick - 1978 Amateur Draft (# 92 - Mel Hewitt) | To Pittsburgh Penguins Randy Carlyle George Ferguson | |
| June 14, 1978 | To Pittsburgh Penguins Tom Bladon Orest Kindrachuk Ross Lonsberry | To Philadelphia Flyers 1st-rd pick - 1978 Amateur Draft (# 6 - Behn Wilson) future considerations1 (8th-rd pick - 1978 Amateur Draft - # 126 - Jerry Price) | |
| June 14, 1978 | To Toronto Maple Leafs Paul Harrison | To Minnesota North Stars 4th-rd pick - 1981 Entry Draft (# 69 - Terry Tait) | |
| June 14, 1978 | To Toronto Maple Leafs Dave Hutchison Lorne Stamler | To Los Angeles Kings Scott Garland Brian Glennie Kurt Walker 2nd-rd pick - 1979 Entry Draft (# 30 - Mark Hardy) | |
| June 15, 1978 | To Minnesota North Stars 2nd-rd pick - 1981 Entry Draft (# 41 - Jali Wahlsten) | To St. Louis Blues Bob Stewart future considerations2 (Harvey Bennett Jr.) | |
| June 15, 1978 | To Colorado Rockies 2nd-rd pick - 1978 Amateur Draft (# 27 - Merlin Malinowski) | To Philadelphia Flyers 2nd-rd pick - 1979 Entry Draft (# 22 - Blake Wesley) | |
| June 15, 1978 | To St. Louis Blues 7th-rd pick - 1978 Amateur Draft (# 109 - Paul MacLean) 9th-rd pick - 1978 Amateur Draft (# 143 - Rick Simpson) 10th-rd pick - 1978 Amateur Draft (# 160 - Bob Froese) 11th-rd pick - 1978 Amateur Draft (# 175 - Dan Hermansson) 12th-rd pick - 1978 Amateur Draft (# 191 - Don Boyd) 13th-rd pick - 1978 Amateur Draft (# 205 - Carl Bloomberg) 14th-rd pick - 1978 Amateur Draft (# 216 - Joe Casey) | To Pittsburgh Penguins cash | |
| June 15, 1978 | To Philadelphia Flyers 10th-rd pick - 1978 Amateur Draft (# 167 - Rick Berard) 11th-rd pick - 1978 Amateur Draft (# 182 - Mark Berge) | To Buffalo Sabres cash | |
| June 15, 1978 | To Boston Bruins cash | To St. Louis Blues 10th-rd pick - 1978 Amateur Draft (# 170 -Dan Lerg) 11th-rd pick - 1978 Amateur Draft (# 185 - John Sullivan) 12th-rd pick - 1978 Amateur Draft (# 200 - Gerd Truntschka) 13th-rd pick - 1978 Amateur Draft (# 211 - Mike Pidgeon) | |
| June 15, 1978 | To Toronto Maple Leafs cash | To St. Louis Blues 11th-rd pick - 1978 Amateur Draft (# 181 - Jean-Francois Boutin) 12th-rd pick - 1978 Amateur Draft (# 197 - Paul Stasiuk) 13th-rd pick - 1978 Amateur Draft (# 212 - Brian Crombeen) 14th-rd pick - 1978 Amateur Draft (# 221 - Blair Wheeler) | |
| June 15, 1978 | To Vancouver Canucks cash | To Washington Capitals 12th-rd pick - 1978 Amateur Draft (# 189 - Steve Barger) | |
| June 15, 1978 | To Chicago Black Hawks cash | To Philadelphia Flyers 12th-rd pick - 1978 Amateur Draft (# 195 - Jim Olson) | |
| June 15, 1978 | To Los Angeles Kings cash | To St. Louis Blues 13th-rd pick - 1978 Amateur Draft (# 207 - Terry Kitching) 14th-rd pick - 1978 Amateur Draft (# 218 - Jim Farrell) | |
| June 15, 1978 | To Atlanta Flames cash | To St. Louis Blues 13th-rd pick - 1978 Amateur Draft (# 209 - Brian O'Connor) 14th-rd pick - 1978 Amateur Draft (# 220 - Frank Johnson) | |
| June 15, 1978 | To Colorado Rockies cash | To Washington Capitals 14th-rd pick - 1978 Amateur Draft (# 215 - Ray Irwin) | |
| June 16, 1978 | To Vancouver Canucks rights to Thomas Gradin | To Chicago Black Hawks 2nd-rd pick - 1980 Entry Draft3 (# 28 - Steve Ludzik) |
| July 27, 1978 | To Minnesota North Stars rights to Jack Carlson | To Detroit Red Wings future considerations |
| August 8, 1978 | To Minnesota North Stars cash | To St. Louis Blues Bob Murdoch | |
| August 31, 1978 | To Colorado Rockies Joe Watson | To Philadelphia Flyers cash |
| September 6, 1978 | To Boston Bruins Dick Redmond | To Atlanta Flames Gregg Sheppard | |
| September 6, 1978 | To Atlanta Flames Jean Pronovost | To Pittsburgh Penguins Gregg Sheppard | |
| September 13, 1978 | To Toronto Maple Leafs Garry Monahan | To Vancouver Canucks cash | |
| September 18, 1978 | To Boston Bruins future considerations | To Los Angeles Kings Doug Halward |
| November, 1978 exact date unknown | To Colorado Rockies Don Awrey | To New York Rangers cash | |
| November 4, 1978 | To Atlanta Flames Rod Seiling | To St. Louis Blues cash | |
| November 17, 1978 | To Vancouver Canucks Dunc Wilson | To Pittsburgh Penguins cash | |
| November 18, 1978 | To Colorado Rockies Nick Beverley | To Los Angeles Kings 4th-rd pick - 1982 Entry Draft (# 64 - Dave Gans) |
| December 6, 1978 | To Los Angeles Kings rights to Steve Carlson | To Detroit Red Wings Steve Short | |
| December 29, 1978 | To Vancouver Canucks Drew Callander Kevin McCarthy | To Philadelphia Flyers Dennis Ververgaert | |
| December 31, 1978 | To Los Angeles Kings Randy Holt | To Vancouver Canucks Don Kozak |
| January 16, 1979 | To Los Angeles Kings Richard Mulhern 2nd-rd pick - 1980 Entry Draft (CGY - # 31 - Tony Curtale)1 | To Atlanta Flames Bob Murdoch 2nd-rd pick - 1980 Entry Draft (# 34 - Dave Morrison) |
| February 6, 1979 | To Buffalo Sabres Dave Schultz | To Pittsburgh Penguins Gary McAdam |
| March 3, 1979 | To Colorado Rockies Don Saleski | To Philadelphia Flyers future considerations | |
| March 12, 1979 | To Buffalo Sabres 3rd-rd pick - 1979 Entry Draft (# 55 - Jacques Cloutier) 3rd-rd pick - 1980 Entry Draft (# 56 - Sean McKenna) | To New York Rangers Jocelyn Guevremont | |
| March 12, 1979 | To Minnesota North Stars future considerations | To Washington Capitals Chuck Arnason | |
| March 13, 1979 | To Toronto Maple Leafs Paul Gardner | To Colorado Rockies Don Ashby Trevor Johansen | |
| March 13, 1979 | To Atlanta Flames Ivan Boldirev Darcy Rota Phil Russell | To Chicago Black Hawks Greg Fox Tom Lysiak Harold Phillipoff Pat Ribble Miles Zaharko |
| April 24, 1979 | To Minnesota North Stars Chuck Arnason | To Washington Capitals cash |