Early into the 2006–07 season, Lambert was purchased for £200,000 from Rochdale by Bristol Rovers in a move finalised on 31 August 2006, transfer deadline day.
Despite quickly establishing himself as a regular member of the squad, it took Lambert until November to score his first goal for the club, in the last minute of a 2–0 win over Barnet.
The remainder of the season proved to be a disappointment for the forward, although an 86th-minute goal in the last league match of the season against Hartlepool United ultimately sent Bristol Rovers into the League Two Play-offs, from which they won promotion to League One.
Lambert also scored the only goal in the Football League Trophy Southern Area Final in a Bristol derby against local rivals Bristol City, which ultimately sent the team into the final with Doncaster Rovers (which they lost 2–3 after extra time).

In 2007–08, Lambert appeared in every match of the season for Bristol Rovers, scoring a total of 19 goals in all competitions Lambert proved to be most useful in the FA Cup, scoring goals in both legs of the First Round against Leyton Orient, two goals in the 5–1 Second Round win over Rushden & Diamonds, the only goal in the Fourth Round win against Barnet, and the only goal in the Fifth Round win against Southampton, scored in the last ten minutes of the match.
Despite his relatively low scoring record, Lambert finished as the club's top scorer for the season.

In the following season, Lambert established himself as one of League One's best players by finishing as the season's joint-top scorer of 29 goals with Swindon Town's Simon Cox – a performance which also resulted in his first inclusion in the League One PFA Team of the Year.
Throughout the season, in which Rovers finished a respectable 11th in the league, Lambert put in a number of impressive performances, including scoring all four goals in a 4–2 win against Southend United, and scoring a hat-trick in a 3–0 away win against Hereford United.
Early into the 2006–07 season, Lambert was purchased for £200,000 from Rochdale by Bristol Rovers in a move finalised on 31 August 2006, transfer deadline day. Despite quickly establishing himself as a regular member of the squad, it took Lambert until November to score his first goal for the club, in the last minute of a 2–0 win over Barnet. The remainder of the season proved to be a disappointment for the forward, although an 86th-minute goal in the last league match of the season against Hartlepool United ultimately sent Bristol Rovers into the League Two Play-offs, from which they won promotion to League One. Lambert also scored the only goal in the Football League Trophy Southern Area Final in a Bristol derby against local rivals Bristol City, which ultimately sent the team into the final with Doncaster Rovers (which they lost 2–3 after extra time).
In 2007–08, Lambert appeared in every match of the season for Bristol Rovers, scoring a total of 19 goals in all competitions Lambert proved to be most useful in the FA Cup, scoring goals in both legs of the First Round against Leyton Orient, two goals in the 5–1 Second Round win over Rushden & Diamonds, the only goal in the Fourth Round win against Barnet, and the only goal in the Fifth Round win against Southampton, scored in the last ten minutes of the match. Despite his relatively low scoring record, Lambert finished as the club's top scorer for the season.
In the following season, Lambert established himself as one of League One's best players by finishing as the season's joint-top scorer of 29 goals with Swindon Town's Simon Cox – a performance which also resulted in his first inclusion in the League One PFA Team of the Year. Throughout the season, in which Rovers finished a respectable 11th in the league, Lambert put in a number of impressive performances, including scoring all four goals in a 4–2 win against Southend United, and scoring a hat-trick in a 3–0 away win against Hereford United.
Rickie Lambert